# List of professional services firms in the United Kingdom
Tamtam tracks 2,706 professional services firms headquartered in the United Kingdom. This list ranks the 100 largest by number of employees on LinkedIn, led by EY, FUJITSU and G4S. Their median headcount is 5,881. Half of them were founded in 1985 or later. The most common headquarters are London (73).
This selection of professional services firms in the United Kingdom primarily comprises large enterprises. It includes global players such as EY, which offers assurance, consulting, law, strategy, tax, and transactions, and Fujitsu, a global information and communication technology company. Other notable firms are G4S, a security and facility services provider, and Aon, which provides advice and solutions to clients worldwide.
The companies listed cover a broad spectrum of professional services, ranging from IT services and consulting, exemplified by Serco and Capita, to financial services, with Aon and WTW. A significant concentration of headquarters is in London, including those of EY, G4S, Aon, and WTW, indicating a central hub for these operations within the UK.
π¬π§ United Kingdom Β· 100 companies Β· Updated Nov 12, 2026
| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [EY](https://www.tamtam.ai/c/ey) (ey.com)
A global organization with diverse teams in over 150 countries provides assurance, consulting, law, strategy, tax, and transactions to help clients grow and transform | Professional Services | π¬π§ London | 404,207 | |
| 2 | [FUJITSU](https://www.tamtam.ai/c/fujitsu) (global.fujitsu)
Leading global information and communication technology company, offering technology products, solutions, and services, connecting people, technology, and ideas for a sustainable world. | IT Services and IT Consulting | π¬π§ | 124,000 | 1935 |
| 3 | [G4S](https://www.tamtam.ai/c/g4s) (g4s.com)
A leading security and facility services company providing proactive security services, cutting-edge technology, and integrated solutions to help clients focus on their core business | Security and Investigations | π¬π§ London | 116,486 | 1901 |
| 4 | [Aon](https://www.tamtam.ai/c/aon) (aon.com)
The company provides advice and solutions to clients worldwide, helping them make better decisions to protect and grow their business | Financial Services | π¬π§ London | 93,574 | |
| 5 | [WTW](https://www.tamtam.ai/c/wtw) (wtwco.com)
Offering data-driven solutions in people, risk, and capital areas, leveraging global expertise to enhance strategy, resilience, workforce motivation, and performance | Financial Services | π¬π§ London | 55,656 | |
| 6 | [Serco](https://www.tamtam.ai/c/serco-hook) (serco.com)
Innovative solutions for global challenges in justice, migration, defense, space, health, and transport through service design, program management, and systems integration | IT Services and IT Consulting | π¬π§ Hook | 32,618 | |
| 7 | [Hays](https://www.tamtam.ai/c/hays) (haysplc.com)
Specialist recruitment and workforce solutions provider offering advisory services, career transitions, and employer brand positioning, with a focus on empowering people and businesses to succeed globally | Staffing and Recruiting | π¬π§ London | 31,854 | |
| 8 | [Arup](https://www.tamtam.ai/c/arup) (arup.com)
A global collective of designers and consultants dedicated to sustainable development, collaborating with clients to shape a better world using technology and imagination | Design Services | π¬π§ London | 26,193 | 1946 |
| 9 | [Capita](https://www.tamtam.ai/c/capita) (capita.com)
A leading provider of business services using data, technology, and people to simplify connections between governments, citizens, businesses, and customers | IT Services and IT Consulting | π¬π§ London | 25,581 | 1984 |
| 10 | [Kantar](https://www.tamtam.ai/c/kantar) (kantar.com)
Global leader in marketing data and analytics with deep expertise, innovative technology, and insights to help clients understand people and drive growth worldwide | Market Research | π¬π§ London | 24,976 | |
| 11 | [Mott MacDonald](https://www.tamtam.ai/c/mott-macdonald) (mottmac.com)
The company focuses on improving society through digital innovation, excellence, and solving intricate challenges with clients to deliver better outcomes | Civil Engineering | π¬π§ London | 24,653 | 1989 |
| 12 | [Computacenter](https://www.tamtam.ai/c/computacenter) (computacenter.com)
A leading technology and services provider, trusted by large organizations, helping customers manage and transform their technology infrastructure for digital transformation | IT Services and IT Consulting | π¬π§ Hatfield | 20,070 | 1981 |
| 13 | [EY-Parthenon](https://www.tamtam.ai/c/ey-parthenon) (ey.com)
Multidisciplinary professionals across 120 countries provide actionable corporate, transaction, and turnaround strategies to clients using data analytics and digital capabilities | Business Consulting and Services | π¬π§ London | 18,536 | |
| 14 | [Michael Page](https://www.tamtam.ai/c/michael-page) (redirect.michaelpage.com)
Professional services recruitment with specialized teams offering local market knowledge and international network support across multiple industries and regions. | Staffing and Recruiting | π¬π§ Addlestone | 15,725 | |
| 15 | [KPMG UK](https://www.tamtam.ai/c/kpmg-uk) (kpmg.com)
A leading UK provider of tax, audit, and advisory services with a global presence, focusing on innovative solutions and expertise for clients' needs | Business Consulting and Services | π¬π§ London | 15,102 | 1987 |
| 16 | [Petrofac](https://www.tamtam.ai/c/petrofac) (petrofac.com)
International energy service provider specializing in designing, building, managing, and maintaining oil, gas, refining, and renewable energy infrastructure for leading energy companies worldwide | Engineering Services | π¬π§ London | 14,616 | 1981 |
| 17 | [Cloud Consulting](https://www.tamtam.ai/c/cloud-consulting) (ccltng.com)
Oversees national education policies, youth programs, and administration to support learning and development across France. | IT Services and IT Consulting | π¬π§ London | 14,588 | |
| 18 | [Savills](https://www.tamtam.ai/c/savills) (savills.com)
Global real estate advisory firm providing tailored solutions and expert advice for residential and commercial property clients worldwide. | Real Estate | π¬π§ London | 13,891 | |
| 19 | [Smollan](https://www.tamtam.ai/c/smollan) (smollan.com)
Partners with brands and retailers, building solutions that drive growth and create opportunities at the point of purchase. | Retail | π¬π§ London | 13,502 | 1931 |
| 20 | [Rentokil Initial](https://www.tamtam.ai/c/rentokil-initial) (rentokil-initial.com)
Global provider of pest control, hygiene, and well-being services protecting people and enhancing lives for commercial and private customers. | Environmental Services | π¬π§ Crawley | 12,515 | 1925 |
| 21 | [RSK Group](https://www.tamtam.ai/c/rsk-group) (rskgroup.com)
Global provider of environmental consultancy and engineering services, integrating innovation and multidisciplinary collaboration to address complex sustainability challenges. | Environmental Services | π¬π§ Helsby | 12,442 | |
| 22 | [Amey](https://www.tamtam.ai/c/amey) (amey.com)
A leading provider of engineering, operations, and decarbonisation solutions for transport infrastructure and complex facilities, focusing on sustainability and resilience | Civil Engineering | π¬π§ London | 11,000 | |
| 23 | [PwC UK](https://www.tamtam.ai/c/pwc-uk) (pwc.co.uk)
Professional services firm focusing on building trust in society and solving important problems through partnership and commercial expertise. | Accounting | π¬π§ London | 10,873 | |
| 24 | [BSI](https://www.tamtam.ai/c/bsi-london) (bsigroup.com)
A global organization with over 100 years of experience in shaping best practices, helping businesses achieve excellence, competence, and sustainable growth | Professional Services | π¬π§ London | 9,882 | 1901 |
| 25 | [Mace](https://www.tamtam.ai/c/mace) (macegroup.com)
Delivery consultancy and construction expertise for iconic buildings, data centres, life science, social infrastructure, and regeneration projects worldwide. | Construction | π¬π§ London | 9,872 | 1990 |
| 26 | [Atkins](https://www.tamtam.ai/c/atkins) (atkinsrealis.com)
World-class engineering services and nuclear organization connecting people, data, and technology to transform global infrastructure and energy systems through design and management. | Engineering Services | π¬π§ Epsom | 9,798 | |
| 27 | [Endava](https://www.tamtam.ai/c/endava) (endava.com)
The company leverages technology and expertise to drive innovation and transform businesses with customized digital solutions across industries | IT Services and IT Consulting | π¬π§ London | 9,559 | 2020 |
| 28 | [Apex Group Ltd (UK & Ireland)](https://www.tamtam.ai/c/apex-group-ltd-uk-and-ireland) (apexgroup.com)
A global financial services provider with offices in over 50 countries, offering a wide range of services to asset managers, capital markets, and family offices | Financial Services | π¬π§ London | 9,281 | 2003 |
| 29 | [AMS](https://www.tamtam.ai/c/ams) (weareams.com)
Global talent solutions business specializing in sourcing, selecting, and retaining top talent through digital innovation, HR expertise, and a holistic approach to workforce management | Human Resources Services | π¬π§ London | 8,718 | 1996 |
| 30 | [SCC](https://www.tamtam.ai/c/scc) (scc.com)
SCC is a leading IT group in Europe, providing limitless IT solutions, cyber security services, digital workplace solutions, and hybrid infrastructure services | IT Services and IT Consulting | π¬π§ Birmingham | 8,687 | 1975 |
| 31 | [Supporting Education Group](https://www.tamtam.ai/c/supporting-education-group) (supportingeducation.com)
Providing qualified teachers, support staff, professional development, and tailored services to improve education quality for schools and disadvantaged students. | Education | π¬π§ London | 8,571 | |
| 32 | [Clifford Chance](https://www.tamtam.ai/c/clifford-chance) (cliffordchance.com)
A global law firm providing high-quality legal advice to a diverse range of clients, including corporations, governments, regulators, and non-profit organizations worldwide | Law Practice | π¬π§ London | 8,435 | 1987 |
| 33 | [DNEG](https://www.tamtam.ai/c/dneg-fitzrovia) (dneg.com)
A global visual entertainment services company acclaimed for its award-winning visual effects work in feature films, television, and multiplatform content | Animation and Post-production | π¬π§ Fitzrovia | 8,179 | 1998 |
| 34 | [Capco](https://www.tamtam.ai/c/capco) (capco.com)
Global technology and management consultancy specializing in digital transformation, data-driven solutions, and innovation for banking, payments, capital markets, insurance, and energy sectors. | Financial Services | π¬π§ London | 8,026 | 1998 |
| 35 | [SThree](https://www.tamtam.ai/c/sthree) (sthree.com)
Connecting skilled STEM professionals with organizations to drive innovation and solve complex challenges through specialist brands and tailored workforce solutions. | Business Consulting and Services | π¬π§ London | 7,927 | |
| 36 | [Acuity Analytics](https://www.tamtam.ai/c/acuity-analytics) (acuityanalytics.com)
Provides bespoke research, analytics, and technology solutions to financial services, helping institutions operate efficiently and unlock human capital to drive revenue. | Financial Services | π¬π§ London | 7,619 | 2003 |
| 37 | [Azets](https://www.tamtam.ai/c/azets) (azets.com)
A leading professional services firm in Northern Europe, providing advisory, accounting, audit, HR, recruitment, outsourcing, and technology solutions to clients | Accounting | π¬π§ London | 7,523 | |
| 38 | [Clyde & Co](https://www.tamtam.ai/c/clyde-and-co) (clydeco.com)
A global law firm specializing in insurance, transport, infrastructure, energy, and trade Committed to diversity, community support, and environmental sustainability | Law Practice | π¬π§ London | 7,472 | 1933 |
| 39 | [Linklaters](https://www.tamtam.ai/c/linklaters) (linklaters.com)
It is a global law firm providing legal expertise and innovative solutions to clients navigating complex markets and regulatory environments. | Law Practice | π¬π§ London | 7,110 | |
| 40 | [Freshfields](https://www.tamtam.ai/c/freshfields) (freshfields.com)
Global law firm supporting leading corporations, financial institutions, and governments on ground-breaking mandates worldwide through 2,800+ lawyers in multiple offices | Law Practice | π¬π§ London | 6,920 | 1743 |
| 41 | [BDO UK](https://www.tamtam.ai/c/bdo-uk) (bdo.co.uk)
Provides tax, audit, assurance, accounting, business advisory, and outsourcing services to diverse sectors with a client-focused, innovative approach. | Accounting | π¬π§ London | 6,800 | 1903 |
| 42 | [Reed](https://www.tamtam.ai/c/reed) (reed.com)
A leading family-run recruitment agency since 1960, offering specialist services and the UK's largest candidate database to fill various job positions | Staffing and Recruiting | π¬π§ London | 6,669 | 1960 |
| 43 | [Knight Frank](https://www.tamtam.ai/c/knight-frank) (knightfrank.com)
A global property advisory firm offering personalized advice, expert client service, and a respectful online community for commercial and residential properties | Real Estate | π¬π§ London | 6,432 | |
| 44 | [Toptal](https://www.tamtam.ai/c/toptal) (toptal.com)
A network connecting top talent in business, design, and technology to help companies scale teams on demand with impressive growth | Software Development | π¬π§ Work from Anywhere | 6,417 | 2010 |
| 45 | [Compass Group UK & Ireland](https://www.tamtam.ai/c/compass-group-uk-and-ireland) (compass-group.co.uk)
We provide great tasting food, memorable experiences, support services, and inspiration to brighten every day for clients and customers | Food and Beverage Services | π¬π§ Chertsey | 6,301 | |
| 46 | [Eversheds Sutherland](https://www.tamtam.ai/c/eversheds-sutherland) (eversheds-sutherland.com)
Global law practice offering high quality, innovative solutions for diverse clients worldwide, specializing in complex business issues with a people-focused approach | Law Practice | π¬π§ London | 6,217 | |
| 47 | [Qualitest](https://www.tamtam.ai/c/qualitest) (quality-ai.com)
Global leader in AI-powered Quality Engineering services, specializing in superior customer experience, accelerated release velocity, and tailored solutions for various industries | IT Services and IT Consulting | π¬π§ London | 6,088 | 1997 |
| 48 | [Grant Thornton UK](https://www.tamtam.ai/c/grant-thornton-uk) (grantthornton.co.uk)
Providing assurance, tax, and advisory services through a global network, combining local insight with flexible, client-focused solutions. | Accounting | π¬π§ London | 5,972 | 1904 |
| 49 | [Acacium Group](https://www.tamtam.ai/c/acacium-group) (linktr.ee)
Global healthcare delivery partner with 40+ years experience offering workforce access, technology, and expertise to improve healthcare, social care, and life sciences worldwide | Hospitals and Health Care | π¬π§ London | 5,961 | |
| 50 | [Lloyd's Register](https://www.tamtam.ai/c/lloyd-s-register) (lr.org)
Provides professional engineering and technology services to improve safety and performance of critical infrastructures worldwide, supporting engineering research and education. | Maritime Transportation | π¬π§ London | 5,881 | 1760 |
| 51 | [RPS](https://www.tamtam.ai/c/rps) (rpsgroup.com)
Global consulting and engineering firm part of Tetra Tech, providing services in property, energy, transport, water, resources, defense, and government sectors | Business Consulting and Services | π¬π§ Abingdon | 5,846 | |
| 52 | [Element Materials Technology](https://www.tamtam.ai/c/element-materials-technology) (element.com)
Global provider of testing, inspection, and certification services ensuring product safety, regulatory compliance, and sustainability across advanced industrial supply chains. | Manufacturing | π¬π§ London | 5,829 | 2011 |
| 53 | [NHS Professionals](https://www.tamtam.ai/c/nhs-professionals) (nhsprofessionals.nhs.uk)
Provision of flexible, cost-effective healthcare staff including nurses, doctors, and administrative professionals to support NHS trusts efficiently. | Staffing and Recruiting | π¬π§ Hemel Hempstead | 5,807 | 2004 |
| 54 | [Vialto](https://www.tamtam.ai/c/vialto) (vialtopartners.com)
Global mobility ecosystem transformation through tax, immigration, compensation, and work strategy solutions for multinational organizations in 150+ countries | Business Consulting and Services | π¬π§ London | 5,717 | |
| 55 | [Davies](https://www.tamtam.ai/c/davies) (davies-group.com)
Specialist professional services and technology firm providing risk management, business process optimization, and digital transformation solutions to insurance, regulated, and global businesses | Insurance | π¬π§ London | 5,693 | |
| 56 | [QinetiQ](https://www.tamtam.ai/c/qinetiq) (qinetiq.com)
Integrated global defence and security company focused on mission-led innovation, testing technologies, and enabling customers to deploy enhanced capabilities for protecting lives. | Defense and Space Manufacturing | π¬π§ Farnborough | 5,512 | |
| 57 | [PA Consulting](https://www.tamtam.ai/c/pa-consulting) (paconsulting.com)
Global teams of strategists, technologists, and experts deliver innovative solutions across industries to drive transformation and lasting client success. | Business Consulting and Services | π¬π§ London | 5,470 | |
| 58 | [SS&C GlobeOp](https://www.tamtam.ai/c/ss-and-c-globeop) (ssctech.com)
Global provider of cloud-based fund services and technology for hedge funds, private equity, and asset managers, offering outsourcing support for operational efficiency and risk reduction | Financial Services | π¬π§ London | 5,416 | 2000 |
| 59 | [Teaching Personnel](https://www.tamtam.ai/c/teaching-personnel) (teachingpersonnel.com)
Specializes in recruiting teachers and classroom support staff for UK schools, providing staffing, tutoring, and supply services. | Staffing and Recruiting | π¬π§ Welwyn Garden City | 5,388 | |
| 60 | [Computer Futures](https://www.tamtam.ai/c/computer-futures) (computerfutures.com)
A global STEM recruitment company connecting businesses with highly skilled IT talent for over 30 years through specialized IT market expertise | IT Services and IT Consulting | π¬π§ London | 5,349 | 1986 |
| 61 | [Ashurst](https://www.tamtam.ai/c/ashurst) (ashurst.com)
Leading global law firm offering legal, risk consulting, and NewLaw services. Manages complex multi-jurisdictional transactions, disputes, and projects for corporates, financial institutions, and governments. | Law Practice | π¬π§ London | 5,236 | |
| 62 | [Agricultural and Farming Jobs](https://www.tamtam.ai/c/agricultural-and-farming-jobs) (agrifj.co.uk)
Specialist Agricultural Recruitment Agency offering headhunting and job advertising services for Agricultural, Farming, Horticultural, Veterinary, and related clients worldwide | Staffing and Recruiting | π¬π§ Bromsgrove | 5,132 | 2013 |
| 63 | [Monks](https://www.tamtam.ai/c/monks) (monks.com)
Provides global marketing, technology services, AI-driven data science, and content production to help brands accelerate business and outpace competition. | Advertising Services | π¬π§ London | 5,067 | 2001 |
| 64 | [RSM UK](https://www.tamtam.ai/c/rsm-uk) (rsmuk.com)
Professional services network providing expertise, resources, and client-focused solutions to empower businesses with confidence and deep understanding. | Accounting | π¬π§ London | 5,025 | 1988 |
| 65 | [Fashion](https://www.tamtam.ai/c/fashion) (growth.me.uk)
Creative collective offering design, patternmaking, sampling, production, styling, photography, and marketing services for fashion brands and designers. | Retail Apparel and Fashion | π¬π§ London | 4,979 | 2017 |
| 66 | [NG Bailey](https://www.tamtam.ai/c/ng-bailey) (ngbailey.com)
A leading UK engineering and services business with a focus on excellence, integration, apprenticeship schemes, and investing in training and development | Construction | π¬π§ Leeds | 4,914 | 1921 |
| 67 | [Almac Group](https://www.tamtam.ai/c/almac-group) (almacgroup.com)
Providing drug development, biomarker discovery, clinical trial supply, analytical services, and commercial manufacturing solutions for pharmaceutical and biotech companies worldwide. | Pharmaceutical Manufacturing | π¬π§ Craigavon | 4,888 | 1968 |
| 68 | [Logicalis](https://www.tamtam.ai/c/logicalis) (logicalis.com)
A global technology service provider helping organizations succeed in a digital-first world through cloud, connectivity, collaboration, and security solutions | IT Services and IT Consulting | π¬π§ Maidenhead | 4,868 | 1998 |
| 69 | [DWF](https://www.tamtam.ai/c/dwf) (dwfgroup.com)
Global provider of integrated legal and business services across various sectors, offering bespoke solutions for clients with efficiency, price certainty, and transparency | Law Practice | π¬π§ London | 4,848 | 1977 |
| 70 | [RSS Global](https://www.tamtam.ai/c/rss-global) (rssglobal.com)
A portfolio of staffing brands specializing in workforce solutions across various sectors in the UK, Ireland, and Asia Pacific | Staffing and Recruiting | π¬π§ London | 4,535 | |
| 71 | [Robert Walters](https://www.tamtam.ai/c/robert-walters) (robertwalters.co.uk)
Providing recruitment, outsourcing, and advisory services globally to connect organizations with skilled professionals for permanent, temporary, or interim roles. | Staffing and Recruiting | π¬π§ London | 4,508 | 1985 |
| 72 | [Pinsent Masons](https://www.tamtam.ai/c/pinsent-masons) (pinsentmasons.com)
Multinational professional services firm, legal foundation, diverse skill sets, technology, processes, competitive advantage clients, business-critical advice complex regulatory environments. | Law Practice | π¬π§ London | 4,403 | |
| 73 | [SLR Consulting](https://www.tamtam.ai/c/slr-consulting) (slrconsulting.com)
Providing expert sustainability consulting and advisory services globally, partnering with clients to solve complex environmental challenges collaboratively. | Environmental Services | π¬π§ London | 4,311 | 1994 |
| 74 | [FDM Group](https://www.tamtam.ai/c/fdm-group) (fdmgroup.com)
global business and technology consultancy powering tech innovation, launching careers, partnering with companies, emphasizing diversity and inclusivity worldwide | IT Services and IT Consulting | π¬π§ London | 4,132 | 1991 |
| 75 | [Accenture UK & Ireland](https://www.tamtam.ai/c/accenture-uk-and-ireland) (accenture.com)
A global professional services company leveraging technology, innovation, and industry expertise to drive digital transformation and deliver tangible outcomes for clients worldwide | IT Services and IT Consulting | π¬π§ London | 4,101 | |
| 76 | [RSM](https://www.tamtam.ai/c/rsm) (rsm.global)
Global network providing assurance, tax, and consulting services focused on middle-market businesses with client-centric, insightful, and resource-sharing approach. | Professional Services | π¬π§ London | 4,090 | 1964 |
| 77 | [UNKNOWN](https://www.tamtam.ai/c/unknown-london) (weareunknown.io)
The company fosters diversity and creativity by facilitating connections, welcoming different perspectives to open up new possibilities in creative communities | Staffing and Recruiting | π¬π§ London | 4,046 | 2018 |
| 78 | [Costain Group PLC](https://www.tamtam.ai/c/costain-group-plc) (costain.com)
A pioneering infrastructure company in the UK, Costain delivers sustainable solutions for energy, water, transportation, and defence markets while focusing on net zero goals and inclusive practices | Civil Engineering | π¬π§ London | 4,021 | 1865 |
| 79 | [Moore Global](https://www.tamtam.ai/c/moore-global) (moore-global.com)
Global accounting and advisory firm with over 37,000 professionals in 114 countries, dedicated to helping clients thrive through expert guidance and support | Accounting | π¬π§ London | 3,884 | 1907 |
| 80 | [Page Personnel](https://www.tamtam.ai/c/page-personnel) (redirect.pagepersonnel.com)
Specialist recruitment services provider with global offices, part of a leading recruitment group since 1994 Trusted by finance, secretarial, logistics sectors for temporary, contract, permanent staff | Staffing and Recruiting | π¬π§ Addlestone | 3,878 | 1994 |
| 81 | [London Commercial Solicitors](https://www.tamtam.ai/c/london-commercial-solicitors)
Specialized team of lawyers offering comprehensive and personalized legal services to businesses and individuals, with a focus on achieving expectations and solving legal issues | Law Practice | π¬π§ London | 3,778 | |
| 82 | [Buro Happold](https://www.tamtam.ai/c/buro-happold) (burohappold.com)
international consultancy providing engineering, design, and advisory services focused on innovative, collaborative solutions for complex global projects | Construction | π¬π§ Bath | 3,763 | 1976 |
| 83 | [Abacus](https://www.tamtam.ai/c/abacus) (abacus-global.com)
Providing industry-focused, technology-driven business transformation solutions through consulting, systems integration, and outsourcing to help clients lead their industries. | IT Services and IT Consulting | π¬π§ London | 3,703 | 1987 |
| 84 | [Blue Arrow](https://www.tamtam.ai/c/blue-arrow) (bluearrow.co.uk)
A leading UK staffing agency with expertise in placing candidates in various sectors, known for excellence in recruitment and employer recognition | Staffing and Recruiting | π¬π§ London | 3,506 | 1959 |
| 85 | [Control Risks](https://www.tamtam.ai/c/control-risks) (controlrisks.com)
Provides specialist risk consultancy services using data and technology to help global organizations maintain security, compliance, and resilience while pursuing growth. | Business Consulting and Services | π¬π§ London | 3,462 | 1975 |
| 86 | [St. Jamesβs Place](https://www.tamtam.ai/c/st-james-s-place) (sjp.co.uk)
Providing personalized financial planning and wealth management services through experienced professionals to help clients achieve their financial goals. | Financial Services | π¬π§ Cirencester | 3,459 | 1991 |
| 87 | [MHA](https://www.tamtam.ai/c/mha) (mha.co.uk)
Offers financial and business strategy services to enterprises and individuals, supporting growth, success, and sustainable wealth creation globally. | Accounting | π¬π§ London | 3,439 | 1880 |
| 88 | [Addleshaw Goddard](https://www.tamtam.ai/c/addleshaw-goddard) (addleshawgoddard.com)
Providing comprehensive legal advice and solutions across over 50 business law areas to clients in more than 100 countries worldwide. | Law Practice | π¬π§ London | 3,391 | 1775 |
| 89 | [NES Fircroft](https://www.tamtam.ai/c/nes-fircroft) (nesfircroft.com)
Global engineering staffing provider with expertise in Oil & Gas, Power & Renewables, Infrastructure, Life Sciences, Mining, Automotive, and Chemicals sectors worldwide Tailored staffing solutions | Staffing and Recruiting | π¬π§ Altrincham | 3,337 | |
| 90 | [Kainos](https://www.tamtam.ai/c/kainos) (kainos.com)
Utilizing technology to solve customer problems, Kainos transforms businesses and improves lives through Digital Services and the Workday Practice globally | IT Services and IT Consulting | π¬π§ Belfast | 3,317 | 1986 |
| 91 | [Hogarth](https://www.tamtam.ai/c/hogarth) (wppproduction.com)
Creative production company combining craft, insight, and technology to bring creative work to life across global locations. | Advertising Services | π¬π§ London | 3,262 | 2008 |
| 92 | [Bird & Bird](https://www.tamtam.ai/c/bird-and-bird) (twobirds.com)
Providing legal services worldwide with expertise in technology and digital transformation, supporting clients across multiple industries and regions. | Law Practice | π¬π§ London | 3,196 | 1846 |
| 93 | [VINCI Facilities](https://www.tamtam.ai/c/vinci-facilities) (vincifacilities.com)
Facilities management and building solutions provider focusing on safety, sustainability, innovation, and long-term value across public and private sectors. | Facilities Services | π¬π§ Watford | 3,191 | 2009 |
| 94 | [DAC Beachcroft](https://www.tamtam.ai/c/dac-beachcroft) (dacbeachcroft.com)
Leading international legal business, partnering with clients for sustainable growth, defending their business and reputation with tailored commercial, transactional, claims, risk, and advisory legal services. | Law Practice | π¬π§ London | 3,183 | |
| 95 | [Irwin Mitchell](https://www.tamtam.ai/c/irwin-mitchell) (irwinmitchell.com)
Providing personal and business legal advice with deep understanding, tailored solutions, and international support through a global network. | Law Practice | π¬π§ United Kingdom | 3,179 | 1912 |
| 96 | [CMS UK](https://www.tamtam.ai/c/cms-uk) (cms.law)
Providing expert legal advice worldwide through a network of independent law firms, combining local knowledge with global strategic insight. | Law Practice | π¬π§ London | 3,160 | |
| 97 | [Mother](https://www.tamtam.ai/c/mother) (motherfamily.com)
A globally respected, independent creative agency with offices worldwide, specializing in creating culturally impactful ideas for a diverse range of clients | Advertising Services | π¬π§ London | 3,065 | 1996 |
| 98 | [Kennedys](https://www.tamtam.ai/c/kennedys) (kennedyslaw.com)
Global law firm specializing in litigation, insurance, and liability sectors with expertise in advisory services Operates worldwide with a focus on regulatory impact | Law Practice | π¬π§ London | 3,028 | 1899 |
| 99 | [Foster + Partners](https://www.tamtam.ai/c/foster-partners) (fosterandpartners.com)
Global architecture and design studio focusing on sustainable urbanism, with diverse international teams and worldwide offices. | Architecture and Planning | π¬π§ London | 3,025 | 1967 |
| 100 | [Tax Consultant](https://www.tamtam.ai/c/tax-consultant) (wearegalloways.com)
A traditional general practice with a specialist tax consulting team supporting accountants, solicitors, and financial advisers in providing high-level services to clients | Accounting | π¬π§ Brighton | 3,015 | |
## How this list is built
Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 12, 2026.
## More company lists in the United Kingdom
- [The largest companies in the United Kingdom](https://www.tamtam.ai/l/largest-companies-united-kingdom) (36,548)
- [Multinational companies in the United Kingdom](https://www.tamtam.ai/l/multinational-companies-united-kingdom) (7,458)
- [Financial services firms in the United Kingdom](https://www.tamtam.ai/l/financial-services-firms-united-kingdom) (3,711)
- [Financial Services companies in the United Kingdom](https://www.tamtam.ai/l/financial-services-companies-united-kingdom) (3,696)
- [Retail chains in the United Kingdom](https://www.tamtam.ai/l/retail-chains-united-kingdom) (3,289)
- [Software Development companies in the United Kingdom](https://www.tamtam.ai/l/software-development-companies-united-kingdom) (2,600)
- [Manufacturers in the United Kingdom](https://www.tamtam.ai/l/manufacturers-united-kingdom) (2,159)
- [Companies with in-house R&D in the United Kingdom](https://www.tamtam.ai/l/r-and-d-companies-united-kingdom) (1,930)
- [IT Services and IT Consulting companies in the United Kingdom](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-united-kingdom) (1,722)
- [Retail companies in the United Kingdom](https://www.tamtam.ai/l/retail-companies-united-kingdom) (1,596)
- [IT services companies in the United Kingdom](https://www.tamtam.ai/l/it-services-companies-united-kingdom) (1,583)
- [Hotel and hospitality groups in the United Kingdom](https://www.tamtam.ai/l/hospitality-groups-united-kingdom) (1,461)
- [Companies with a mobile app in the United Kingdom](https://www.tamtam.ai/l/companies-with-mobile-app-united-kingdom) (1,411)
- [Consulting firms in the United Kingdom](https://www.tamtam.ai/l/consulting-firms-united-kingdom) (1,298)
- [E-commerce companies in the United Kingdom](https://www.tamtam.ai/l/ecommerce-companies-united-kingdom) (1,246)
- [Hardware manufacturers in the United Kingdom](https://www.tamtam.ai/l/hardware-companies-united-kingdom) (1,239)
- [Family-owned companies in the United Kingdom](https://www.tamtam.ai/l/family-owned-companies-united-kingdom) (1,224)
- [Hospitality companies in the United Kingdom](https://www.tamtam.ai/l/hospitality-companies-united-kingdom) (1,204)
- [Critical infrastructure operators in the United Kingdom](https://www.tamtam.ai/l/critical-infrastructure-operators-united-kingdom) (1,195)
- [Wellness and Fitness Services companies in the United Kingdom](https://www.tamtam.ai/l/wellness-and-fitness-services-companies-united-kingdom) (1,151)
- [Retail Apparel and Fashion companies in the United Kingdom](https://www.tamtam.ai/l/retail-apparel-and-fashion-companies-united-kingdom) (1,085)
- [Subscription businesses in the United Kingdom](https://www.tamtam.ai/l/subscription-businesses-united-kingdom) (1,077)
- [Distributors and wholesalers in the United Kingdom](https://www.tamtam.ai/l/distributors-and-wholesalers-united-kingdom) (1,060)
- [Marketing and communications agencies in the United Kingdom](https://www.tamtam.ai/l/marketing-agencies-united-kingdom) (984)
## The same list elsewhere in United Kingdom
- [Professional services firms in Scotland](https://www.tamtam.ai/l/professional-services-firms-scotland) (112)
- [Professional services firms in London](https://www.tamtam.ai/l/professional-services-firms-london) (1,248)
- [Professional services firms in Manchester](https://www.tamtam.ai/l/professional-services-firms-manchester) (86)
- [Professional services firms in Leeds](https://www.tamtam.ai/l/professional-services-firms-leeds) (55)
- [Professional services firms in Edinburgh](https://www.tamtam.ai/l/professional-services-firms-edinburgh) (43)
- [Professional services firms in Birmingham](https://www.tamtam.ai/l/professional-services-firms-birmingham) (37)
- [Professional services firms in Glasgow](https://www.tamtam.ai/l/professional-services-firms-glasgow) (29)
- [Professional services firms in Bristol](https://www.tamtam.ai/l/professional-services-firms-bristol) (25)
## The same list elsewhere
- [Professional services firms in the world](https://www.tamtam.ai/l/professional-services-firms-in-the-world) (24,737)
- [Professional services firms in Europe](https://www.tamtam.ai/l/professional-services-firms-in-europe) (13,698)
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Source: https://www.tamtam.ai/l/professional-services-firms-united-kingdom