Company lists · Data refreshed September 2026

Top 24 Systems integrators based in London, United Kingdom

Name: Systems integrators based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 15, 2026 404 companies tracked

RevenueBase identified 404 systems integrators headquartered in London, United Kingdom as of September 2026 and tracks 6,287 professional contacts across them, including 2,632 with verified work emails. London is the largest hub.

This list covers systems integrators headquartered in London, United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 15, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 15, 2026 86% judged on-target in blind review

404Companies

6,287Contacts tracked

2,632Verified emails

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The 24 largest systems integrators based in London, United Kingdom

Ranked by team size

Top 24 of 404 systems integrators based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 15, 2026. RevenueBase Smart Search rates how each company's information relates to systems integrators: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	ONNEC	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	501-1,000	585 contacts →
	Indirect evidence “Onnec is a leading partner for IT Infrastructure design, installation and operational support services.” Source: RevenueBase Database · checked Sep 15, 2026
2	Zenitech	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	501-1,000	408 contacts →
	Indirect evidence “Zenitech creates technology to transform businesses.” Source: RevenueBase Database · checked Sep 15, 2026
3	Zenzero	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	501-1,000	401 contacts →
	Indirect evidence “We believe successful businesses are underpinned by quality IT infrastructure.” Source: RevenueBase Database · checked Sep 15, 2026
4	Connect	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	201-500	398 contacts →
	Strong evidence “We’re Connect, a global systems integrator and digital transformation expert with over 35 years of experience.” Source: RevenueBase Database · checked Sep 15, 2026
5	ARCH	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	n/a	307 contacts →
	Indirect evidence “Arch has specialised in SAP solutions for over 25 years and our team has extensive experience of SAP technologies and SAP usability.” Source: RevenueBase Database · checked Sep 15, 2026
6	OLR	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	201-500	292 contacts →
	Strong evidence “OLR is a specialist Oracle Retail systems integrator delivering end-to-end omnichannel solutions to enable leading retailers to accelerate business success through system…” Source: RevenueBase Database · checked Sep 15, 2026
7	Total IT Global	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	201-500	286 contacts →
	Indirect evidence “At Total IT Global, we elevate your digital journey with cutting-edge innovation, to achieve your vision of ‘the enterprise of the future’.” Source: RevenueBase Database · checked Sep 15, 2026
8	Eappsys	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	193 contacts →
	Strong evidence “eAppSys is a systems integrator that is focused exclusively on supporting the core enterprise application systems within Oracle On-Premise and Cloud Applications.” Source: RevenueBase Database · checked Sep 15, 2026
9	Maintel Azzurri Communications	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	501-1,000	186 contacts →
	Strong evidence “Maintel is a leading systems integrator and managed services provider, delivering effortless communications solutions to a broad spectrum of businesses in the UK and…” Source: RevenueBase Database · checked Sep 15, 2026
10	LMG Lmgiq.com	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	201-500	153 contacts →
	Indirect evidence “For 40 years, LMG has delivered secure, resilient and proven digital infrastructure solutions across the built environment.” Source: RevenueBase Database · checked Sep 15, 2026
11	Crossover	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	11-50	82 contacts →
	Strong evidence “Crossover is a leading audiovisual systems integrator – we deliver AV that’s high quality, powerful, simple to use, and reliable.” Source: RevenueBase Database · checked Sep 15, 2026
12	Nephos Technologies	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	80 contacts →
	Strong evidence “Nephos Technologies is an independent data systems integrator, specialising in helping organisations transform the way they store, manage and protect their data.” Source: RevenueBase Database · checked Sep 15, 2026
13	Advisority	Partial evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	61 contacts →
	Partial evidence “We are the trusted IT integrator that specialises in making your work flow.” Source: RevenueBase Database · checked Sep 15, 2026
14	FMK	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	n/a	59 contacts →
	Indirect evidence “A full service consultancy company specialising integrating Macintosh and Windows.” Source: RevenueBase Database · checked Sep 15, 2026
15	Diegesis Limited	Partial evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	52 contacts →
	Partial evidence “Diegesis is a business technology and IT systems integration company that specialises in Decision Support Solutions.” Source: RevenueBase Database · checked Sep 15, 2026
16	Electranet UK Limited	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	49 contacts →
	Indirect evidence “Electranet’s mission is to be a preferred partner to the public and private sectors, bringing competitively priced, secure and innovative solutions to the market.” Source: RevenueBase Database · checked Sep 15, 2026
17	Pace Integration	Partial evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	47 contacts →
	Partial evidence “Pace Integration is a unique technology consultancy that solves your integration challenge – focused on enterprise systems integration strategy, architecture and design that is…” Source: RevenueBase Database · checked Sep 15, 2026
18	Influential Software	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	42 contacts →
	Strong evidence “Influential is a boutique systems integrator, and fully certified partner with Microsoft, IBM Cognos, SAP Business Objects, Boomi and Vena, offering licence sales, support…” Source: RevenueBase Database · checked Sep 15, 2026
19	MVS Audio-Visual	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	11-50	42 contacts →
	Indirect evidence “Bringing you the full benefits of audio visual technology.” Source: RevenueBase Database · checked Sep 15, 2026
20	Forge Technologies	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	41 contacts →
	Indirect evidence “Forge Technologies is a digital IT services business focusing on four technology pillars; Digital App & Innovation, Future Workplace, Cloud Optimisation and Network Transformation.” Source: RevenueBase Database · checked Sep 15, 2026
21	Link Media Systems	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	37 contacts →
	Strong evidence “We are systems integrators.” Source: RevenueBase Database · checked Sep 15, 2026
22	R3 Digital	Strong evidence	London, United KingdomHQ checked Sep 15, 2026	11-50	37 contacts →
	Strong evidence “R3 Digital is a Systems Integrator and Salesforce Platinum (Summit) Consulting Partner that specialises in Health and Life Sciences.” Source: RevenueBase Database · checked Sep 15, 2026
23	3li Global	Indirect evidence	London, United KingdomHQ checked Sep 15, 2026	51-200	36 contacts →
	Indirect evidence “Most businesses don't have a CRM problem.” Source: RevenueBase Database · checked Sep 15, 2026
24	ECS Systems LTD	Partial evidence	London, United KingdomHQ checked Sep 15, 2026	11-50	35 contacts →
	Partial evidence “Here at ECS Systems we pride ourselves on providing the highest level of personalised service, to every client.” Source: RevenueBase Database · checked Sep 15, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: systems integrators. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names systems integrators.
Partial evidence: Its own public description names part of systems integrators, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name systems integrators. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 24 of 404 systems integrators based in London, United Kingdom

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Systems integrators based in London, United Kingdom at a glance

As of Sep 15, 2026

41.9%Verified-email coverage

15.6Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · London

Sep 15, 2026Page data refreshed

Companies by employee count

1-10

205

11-50

139

51-200

201-500

501-1,000

1,001-5,000

Email recency for this list is measured across the whole United Kingdom list rather than for London, so it is reported there. Company counts and contact totals on this page are exact for London, over 404 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among systems integrators, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in London, United Kingdom whose own description of what they do matches “systems integrators”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names systems integrators), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among systems integrators, and records with no verified work email. Companies headquartered outside London are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 2,632 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 15, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Systems integrators by metro in the United Kingdom

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names systems integrators, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many systems integrators are there based in London, United Kingdom?

RevenueBase identified 404 systems integrators headquartered in London, United Kingdom as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

ONNEC, headquartered in London, tops this list with the largest team on record.

Which city has the most systems integrators?

London leads with 404 headquartered companies, followed by Birmingham (29) and Manchester (28).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 2,632 verified decision-maker contacts tracked across these 404 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 15, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.