Company lists · Data verified August 2026

Top 25 Accounting outsourcing firms based in London, United Kingdom

Name: Accounting outsourcing firms based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Verified Aug 28, 2026 535 companies tracked

There are 535 accounting outsourcing firms headquartered in London, United Kingdom (RevenueBase, August 2026). RevenueBase tracks 4,731 professional contacts across them, including 1,275 with verified work emails and 145 with mobile numbers. London is the largest hub.

This list covers accounting outsourcing firms headquartered in London, United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Data current as of August 28, 2026.

535Companies

4,731Contacts tracked

1,275Verified emails

145Mobile numbers

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The 25 largest accounting outsourcing firms based in London, United Kingdom

Ranked by team size

Top 25 of 535 accounting outsourcing firms based in London, United Kingdom, ranked by team size, largest first. Data verified Aug 28, 2026. Click a count to unlock that company's people.
#	Company	HQ	Employees	Contacts	Verified emails
1	Outbooks	London	201-500	475	39
2	SKS Business Services	London	501-1,000	321	217
3	GI Outsourcing	London	201-500	317	168
4	Obox Solution LTD	London	201-500	132	12
5	Initor Global UK	London	51-200	108	43
6	Debitam	London	51-200	103	30
7	Affinity Outsourcing Limited	London	51-200	96	32
8	Sapphire Info Solutions P LTD	London	51-200	88	28
9	Base Practice Support LTD Baseline Practice Support Smc-Pvt LTD	London	51-200	75	19
10	Arna Accounting PVT LTD	London	51-200	63	13
11	Stellaripe	London	51-200	57	40
12	Adler Shine	London	51-200	53	38
13	Adroit Accountax LTD	London	11-50	51	3
14	Artifin Accountants	London	11-50	51	1
15	Blinkhorns Accountants	London	51-200	49	36
16	PSB Accountants Limited	London	11-50	42	5
17	Ascendant	London	201-500	39	26
18	Jump Accounting	London	51-200	34	14
19	Bookcheck LTD	London	51-200	29	24
20	Accnet Solutions LTD	London	11-50	20	9
21	Beatons Group	London	11-50	19	17
22	Excelsious	London	11-50	17	3
23	AAT Management Consultants	London	51-200	15	1
24	Asesa Solutions LTD	London	11-50	15	1
25	BM Connect Limited	London	11-50	14	10

Showing 25 of 535 accounting outsourcing firms based in London, United Kingdom

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 1,275 reachable decision-makers.

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Accounting outsourcing firms based in London, United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 535 HQs

145Contacts with mobile numbers

23Emails re-verified in last 30 days

Companies by employee count

1-10

358

11-50

121

51-200

201-500

501-1,000

1,001-5,000

Accounting outsourcing firms by metro in the United Kingdom

Metro	Companies
Accounting outsourcing firms in London	535
Accounting outsourcing firms in Manchester	60
Accounting outsourcing firms in Birmingham	38
Accounting outsourcing firms in Bristol	34
Accounting outsourcing firms in Nottingham	25
Accounting outsourcing firms in Milton Keynes	23
Accounting outsourcing firms in Glasgow	22

How this list was built

Source: The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion: Companies whose own business descriptions match “accounting outsourcing firms”, with match quality audited by blind human judging, and headquartered in London, United Kingdom.
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: Contact records re-verify on a rolling cadence; 23 contacts on this list were re-verified in the last 30 days.
Refresh: Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

How many accounting outsourcing firms are there based in London, United Kingdom?

There are 535 accounting outsourcing firms headquartered in London, United Kingdom as of August 2026 (RevenueBase).

What is the largest company on this list?

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

Which city has the most accounting outsourcing firms?

London leads with 535 headquartered companies, followed by Manchester (60) and Birmingham (38).

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 1,275 verified decision-maker contacts tracked across these 535 companies.

How current is this list?

The list is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 2026.

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About this data

RevenueBase is a B2B contact data platform. Its company graph covers 21.3 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, the same data that powers RevenueBase's B2B data products and the free research portal.