This selection of telecommunications companies in London includes large established groups and mid-sized firms. Many operate globally or have a significant presence across the UK. Vodafone, for example, uses technology to connect people globally and drive social change, while BT Group is a global communications services company. Openreach focuses on being the UK's digital network business, and EE is a mobile communications company offering extensive network coverage.
A notable pattern among these companies is their focus on comprehensive connectivity and digital infrastructure. Several companies, such as Virgin Media O2 and CityFibre, emphasize providing fast broadband and extensive mobile networks. Colt Technology Services is a global digital infrastructure provider, and IHS Towers specializes in tower infrastructure in emerging markets. This indicates a strong emphasis on foundational network services and expansion.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Vodafonevodafone.com
Using technology to connect people globally, drive social change, and improve lives while emphasizing the importance of humanity and collaboration |
142,740 | |||
| 2 | 73,712 | ||||
| 3 |
Openreachopenreach.com
This company is the UK's digital network business, connecting homes, businesses, and more to the world with a focus on high-quality service |
16,885 | |||
| 4 | 12,146 | ||||
| 5 |
Virgin Media O2virginmediao2.co.uk
Provides fastest broadband and largest mobile network in the UK, focusing on customer-first connectivity services and network upgrades. |
8,272 | |||
| 6 |
Vodafone Businessvodafone.com
Providing mobile, fixed, unified communications, IoT, cloud, and security services to businesses globally, regionally, and locally. |
8,100 | |||
| 7 |
Colt Technology Servicescolt.net
Global digital infrastructure provider connecting businesses across 40+ countries with extensive networks, customer-focused innovation, and reliable connectivity solutions. |
5,107 | |||
| 8 |
IHS Towersihstowers.com
A leading tower infrastructure company with over 40,000 towers in emerging markets, specializing in hybrid energy solutions and network monitoring |
3,497 | |||
| 9 |
Liberty Globallibertyglobal.com
Global provider of broadband, mobile communications, and infrastructure investing in fibre, 5G networks, content, technology, and innovation. |
2,833 | |||
| 10 |
Gammagammagroup.co
Gamma is a leading supplier of Unified Communications services in the UK, Germany, Spain, and Benelux, offering robust solutions for communication and collaboration |
2,588 | |||
| 11 |
Telecom Jobstelecomjobs.uk
The company aims to be the top resource for telecom jobs in the UK by connecting jobseekers and employers in the industry |
2,468 | |||
| 12 |
Senture, LLCsenture.com
A premier domestic contact center solutions company providing comprehensive service support nationally, focused on delivering excellent customer experiences and award-winning support services |
2,129 | |||
| 13 |
CityFibrecityfibre.com
We build open-access fiber networks across the UK, providing fast and reliable broadband, Ethernet, and mobile connections to homes, businesses, and institutions |
1,800 | |||
| 14 |
Ofcomofcom.org.uk
Regulating UK communications, ensuring fair home phone and mobile services, overseeing TV, radio, and content, protecting consumers, promoting access to technology |
1,700 | |||
| 15 | 1,407 | ||||
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| 16 |
Lyca Mobile UKlycamobile.co.uk
A global mobile virtual network operator offering low-cost international calls, data, and minutes to 23 countries with a digital-first approach |
1,369 | |||
| 17 |
Hyperoptichyperoptic.com
The company provides ultra-reliable full-fibre broadband with top speeds, no mid-contract price hikes, and exceptional customer service |
1,358 | |||
| 18 |
Boldyn Networksmobilitie.com
A US-based telecommunications infrastructure company providing wireless solutions for robust coverage and 5G services at large venues and cities |
1,286 | |||
| 19 |
Maintelmaintel.co.uk
Provider of cloud communications and managed services, specializing in digital transformation for public and private sectors Delivering digital workplace, customer experience, and secure connectivity solutions globally |
946 | |||
| 20 |
Inmarsatviasat.com
Account closed, follow Viasat company page for satellite communications news due to acquisition. No longer posting here. |
939 | |||
| 21 |
Helios Towersheliostowers.com
Builds, owns, operates telecom passive infrastructure across Africa, enabling mobile operators to expand coverage and improve network access efficiently. |
933 | |||
| 22 |
EXA Infrastructureexainfra.net
A leading digital infrastructure platform in Europe and North America, owning a vast fibre network, data centers, and sub-sea routes for optimal connectivity |
846 | |||
| 23 |
Africell Groupafricell.com
A mobile technology company providing fast, low-cost, and reliable mobile network coverage and innovative services to over sixteen million subscribers in sub-Saharan Africa |
845 | |||
| 24 |
GCXgcxworld.com
Network services enabling digital transformation through managed SD-WAN, hybrid networks, and extensive subsea cloud connectivity across emerging markets and Asia. |
810 | |||
| 25 |
Industriaindustria.com
A leading provider of broadband network and entertainment solutions, offering turn-key services to operators and achieving significant milestones in connectivity and innovation |
788 | |||
| 26 |
Lycatellycagroup.com
The company is a global market leader in the calling card market and Europe's largest International MVNO Mobile brand, serving millions of customers worldwide |
647 | |||
| 27 |
MYCOM OSImycom-osi.com
Provide network assurance and service experience solutions for CSPs and enterprises to manage 5G and enterprise services efficiently. |
557 | |||
| 28 |
Community Fibre Limitedcommunityfibre.co.uk
Provider of London鈥檚 fastest, most reliable, and sustainable full fibre broadband network with excellent customer service and value. |
540 | |||
| 29 |
euNetworkseunetworks.com
A European provider of bandwidth infrastructure services, offering scalable fibre-based products for data center connectivity and cloud services across 17 countries in Europe |
417 | |||
| 30 |
Monty Mobilemontymobile.com
Partnering with operators, enterprises, hyperscalers, and financial institutions to strengthen connectivity, advance technologies, and accelerate digital transformation worldwide with integrated solutions across various domains. |
408 | |||
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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.
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