Top 40 IT companies in London
The 40 most prominent IT companies with a head office in London, ranked by team size, money raised and how many of their people we hold. Every head office is checked against two sources, Crunchbase and the company’s own LinkedIn page, and a company is left out when they disagree.
- Head office: London, England
- Crunchbase category: Information Technology
- Verified IT companies
- 2,163
- People working there now
- 234,993
- Data read
At a glance
BT Group has the largest LinkedIn team on this list, with 69,092 people worldwide. PA Consulting, founded in 1943, is the oldest company in the top 40. The median founding year among the top 40 is 2007, and 4 of them were founded in the last 5 years, including Nscale and Ethos, both founded in 2024.
The 40 most prominent
40 of 2,163 · ranked by team size, funding and reach| # | Company | Head office | Team size | Founded | Last round | Profiles we hold |
|---|---|---|---|---|---|---|
| 1 |  BT Groupbt.com |
London, England | 69,092 | 1969 | Public | 14,919 |
| 2 |  Kantarkantar.com |
London, England | 17,806 | 1992 | Debt | 8,754 |
| 3 |  Endavaendava.com |
London, UK | 9,489 | 2000 | Public | 5,984 |
| 4 |  Nscalenscale.com |
London, England | 989 | 2024 | Debt | 1,018 |
| 5 |  Eburyebury.com |
London | 2,048 | 2009 | Private equity | 2,422 |
| 6 |  Capitacapita.com |
London, England | 26,364 | 1984 | — | 8,738 |
| 7 |  TradingViewtradingview.com |
London, England | 2,624 | 2011 | Series C | 2,309 |
| 8 |  VTEXvtex.com |
London | 2,082 | 2000 | Public | 1,950 |
| 9 |  Teyateya.com |
London, England | 1,206 | 2019 | Series C | 1,479 |
| 10 |  Rightmoverightmove.co.uk |
London, England | 1,243 | 2000 | Public | 1,241 |
| 11 |  Trainlinethetrainline.com |
London, England | 1,184 | 1997 | Public | 1,310 |
| 12 |  Osttraosttra.com |
London, England | 1,374 | 2021 | Secondary sale | 1,362 |
| 13 |  PA Consultingpaconsulting.com |
London | 5,028 | 1943 | — | 4,321 |
| 14 |  Rezolve Airezolve.com |
London, England | 594 | 2016 | Public | 588 |
| 15 |  Colt Technology Servicescolt.net |
London, England | 4,644 | 1992 | — | 4,244 |
| 16 |  GWIgwi.com |
London | 735 | 2009 | Series B | 906 |
| 17 |  Claranetclaranet.co.uk |
London, England | 953 | 1996 | Private equity | 1,043 |
| 18 |  Facultyfaculty.ai |
London, England | 1,134 | 2014 | Non-equity | 1,129 |
| 19 |  FDM Groupfdmgroup.com |
London, England | 4,068 | 1991 | Public | 3,636 |
| 20 |  EXUSexus.co.uk |
London, England | 434 | 1989 | Private equity | 385 |
| 21 |  Improbableimprobable.io |
London, England | 373 | 2012 | Venture round | 500 |
| 22 |  Kaluzakaluza.com |
London, England | 704 | 2009 | Corporate round | 814 |
| 23 |  Options Technologyoptions-it.com |
London, England | 698 | 1993 | Private equity | 710 |
| 24 |  Civicacivica.com |
London | 3,107 | 2001 | — | 3,161 |
| 25 |  RELXrelx.com |
London, UK | 2,485 | 1993 | Public | 2,912 |
| 26 |  PhysicsXphysicsx.ai |
London, England | 323 | 2019 | Series C | 435 |
| 27 | AtlasEdgeatlasedge.com | London, England | 177 | 2021 | Debt | 275 |
| 28 |  Third Bridge Groupthirdbridge.com |
London, Greater London | 2,516 | 2007 | Secondary sale | 2,278 |
| 29 |  CACIcaci.co.uk |
London, England | 2,133 | 1975 | — | 1,984 |
| 30 |  Kape Technologieskape.com |
London, England | 316 | 2011 | Public | 483 |
| 31 | Mthreemthree.com | London, England | 511 | 2010 | Private equity | 627 |
| 32 |  Quantanitequantanite.com |
London | 1,945 | 2014 | — | 1,947 |
| 33 |  InstaDeepinstadeep.com |
London, England | 407 | 2014 | Secondary sale | 513 |
| 34 |  Yotiyoti.com |
London, England | 469 | 2014 | Debt | 525 |
| 35 |  NashTechnashtechglobal.com |
London, England | 1,806 | 2000 | — | 1,560 |
| 36 |  Ethosaskethos.com |
London, England | 561 | 2024 | Series A | 484 |
| 37 |  Gorilla Technology Groupgorilla-technology.com |
London, England | 216 | 2001 | Public | 238 |
| 38 |  QualityAIquality-ai.com |
London, England | 5,435 | 1997 | — | 181 |
| 39 |  Six Degrees6dg.co.uk |
London, England | 303 | 2011 | Venture round | 406 |
| 40 |  Equal Expertsequalexperts.com |
London, England | 1,467 | 2007 | — | 1,374 |
Octopus Investments
DSP
Leah2,123 more verified IT companies in London are in Generect, with the 234,993 people who work at them: names, roles and verified work emails.
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How this list is built
Two sources must agree
Crunchbase files 11,301 IT companies under a London head office. We match each one to its LinkedIn page by domain and keep it only if LinkedIn does not contradict the city or the country: 240 were left out because LinkedIn puts the head office in another city, 358 because it names another country, 73 because the names do not match.
Ranked by substance
The order combines team size on LinkedIn, money raised and how many of the company’s people we hold. It is not a popularity score, and nobody pays to be listed. 2,586 companies with fewer than five people were left out, and so were 4 that now belong to an acquirer, so one employer is not counted twice.
Every number has a date
Each company’s LinkedIn page was read within the last 180 days; 998 with an older read were left out rather than shown with stale numbers. This page was built from data read on .
Questions about IT companies in London
What are the largest IT companies in London?
Of the companies on this list, the largest by team size on LinkedIn are BT Group (69,092), Capita (26,364), Kantar (17,806), Endava (9,489) and QualityAI (5,435). Among those founded in the last ten years, the largest are Osttra, Teya, Nscale, Rezolve Ai and Ethos.
What are the top IT startups in London?
Among companies on this list founded in 2020 or later, the largest by team size on LinkedIn are Osttra (1,374), Nscale (989), Ethos (561) and AtlasEdge (177).
Which IT companies are headquartered in London?
The most prominent are BT Group, Kantar, Endava, Nscale, Ebury, Capita, TradingView, VTEX, Teya and Rightmove. This page lists the top 40; Crunchbase files 11,301 IT companies with a London head office, and 2,163 of them pass our checks.
How many IT companies are there in London?
Crunchbase files 11,301 companies with a London head office under its Information Technology category. 2,163 of them pass our checks: a LinkedIn page that agrees on the city and the country, at least five people, and a company profile read in the last 180 days.
Which London IT companies in this list are the newest?
By founding year: Nscale (2024), Ethos (2024), Osttra (2021), AtlasEdge (2021), Teya (2019) and PhysicsX (2019).
How is this list ranked?
By a combined score of team size on LinkedIn, total money raised and how many of the company's people we hold. Every list in the directory uses this order. It is not a popularity vote and nobody pays to be on it.
How do I find contacts at these companies?
Generect holds 234,993 people working at these 2,163 companies now. Open the list in Generect to filter them by role, seniority and location and to get verified work emails. This page publishes company data only, no personal contact details.
When was this list last updated?
It was built from data read on 7 Oct 2026. The date at the top of the page changes every time the list is rebuilt.
Which are the oldest IT companies in London on this list?
PA Consulting is the oldest (founded 1943), followed by BT Group (1969) and CACI (1975).
Which London companies on this list work on artificial intelligence?
Nscale builds AI data centers and GPU cloud infrastructure. Faculty describes itself as an artificial intelligence company. PhysicsX develops AI-powered engineering software. InstaDeep delivers AI-powered decision-making systems for enterprises.