Company lists · Data verified August 2026

Top 25 Accounting outsourcing firms based in the United Kingdom

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

Compiled by the RevenueBase Data Team Verified Aug 28, 2026 2,644 companies tracked

There are 2,644 accounting outsourcing firms headquartered in the United Kingdom (RevenueBase, August 2026). RevenueBase tracks 15,998 professional contacts across them, including 3,865 with verified work emails and 568 with mobile numbers. London is the largest hub.

This list covers accounting outsourcing firms headquartered in the 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.

2,644Companies

15,998Contacts tracked

3,865Verified emails

568Mobile numbers

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The 25 largest accounting outsourcing firms based in the United Kingdom

Ranked by team size

Top 25 of 2,644 accounting outsourcing firms based in the 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	Burgess Hodgson	Canterbury	51-200	139	40
5	Obox Solution LTD	London	201-500	132	12
6	Intelligent Outsourcing	Tunbridge Wells	51-200	119	56
7	Initor Global UK	London	51-200	108	43
8	FLB Accountants LLP	Winnersh Triangle	51-200	104	71
9	Debitam	London	51-200	103	30
10	SJD Accountancy	Hemel Hempstead	501-1,000	102	2
11	Paperchase Business Services LTD	London Croydon	501-1,000	100	18
12	Rayner Essex LLP	St Albans	51-200	97	72
13	Affinity Outsourcing Limited	London	51-200	96	32
14	Sapphire Info Solutions P LTD	London	51-200	88	28
15	Base Practice Support LTD Baseline Practice Support Smc-Pvt LTD	London	51-200	75	19
16	Isosceles Finance	Cambridge	51-200	68	18
17	Affinity Associates Limited	Wembley	201-500	64	30
18	The Accountancy Partnership	Wirral	51-200	63	33
19	Arna Accounting PVT LTD	London	51-200	63	13
20	Cashroom	Livingston	51-200	56	41
21	Adler Shine	London	51-200	53	38
22	Blinkhorns Accountants	London	51-200	49	36
23	Green & Purple	Cambridge	51-200	44	32
24	Accountsbytes Private Limited	Rugby	51-200	43	3
25	Ascendant	London	201-500	39	26

Showing 25 of 2,644 accounting outsourcing firms based in the United Kingdom

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Accounting outsourcing firms based in the United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 535 HQs

568Contacts with mobile numbers

31Emails re-verified in last 30 days

Companies by employee count

1-10

2,038

11-50

414

51-200

201-500

501-1,000

1,001-5,000

Accounting outsourcing firms by metro

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 the 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; 31 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 the United Kingdom?

There are 2,644 accounting outsourcing firms headquartered in the 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 3,865 verified decision-maker contacts tracked across these 2,644 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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Accounting outsourcing firms by geography

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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.