Company lists · Data refreshed August 2026

Top 25 Accounting outsourcing companies based in London, United Kingdom

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

Compiled by the RevenueBase Data Team Data refreshed Aug 30, 2026 366 companies tracked

There are 366 accounting outsourcing companies headquartered in London, United Kingdom (RevenueBase, August 2026). RevenueBase tracks 3,646 professional contacts across them, including 985 with verified work emails and 104 with mobile numbers. London is the largest hub.

This list covers accounting outsourcing companies 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, how directly it supports the match, and when it was last checked. Data refreshed August 30, 2026.

366Companies

3,646Contacts tracked

985Verified emails

104Mobile numbers

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

Ranked by team size

Top 25 of 366 accounting outsourcing companies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Aug 30, 2026. Evidence rates how directly each company's own description names accounting outsourcing companies: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#	Company	Headquarters	Employees	Contacts	Verified emails
1	OutbooksStrong evidence “Outbooks is a leading provider of outsourcing services to accounting and bookkeeping firms.” Source: company website · checked Aug 30, 2026	London, United Kingdom	201-500	475	39
2	SKS Business ServicesIndirect evidence “At SKS, we pride ourselves on being different.” Source: company website · checked Aug 30, 2026	London, United Kingdom	501-1,000	321	217
3	GI OutsourcingPartial evidence “GI Outsourcing is a UK-based accountants outsourcing firm.” Source: company website · checked Aug 30, 2026	London, United Kingdom	201-500	317	168
4	Obox Solution LTDPartial evidence “At Obox Solution Ltd, we support accounting firms and mid-market businesses by providing tailored virtual staffing solutions for bookkeeping, payroll, CFO services, tax, financial…” Source: company website · checked Aug 30, 2026	London, United Kingdom	201-500	132	12
5	Initor Global UKIndirect evidence “As attention turns to the new fiscal year, accountants across the UK are finalising plans to boost growth and productivity and improve profitability.” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	108	43
6	DebitamPartial evidence “Online Accounting Service \| Bookkeeping \| Payroll \| Personal Tax Return Filing to HMRC \| Corporation Tax Filing \| HMRC ONLINE FILING: Our aim is to help small business owners` tax…” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	103	30
7	Affinity Outsourcing LimitedStrong evidence “Affinity Outsourcing is an accountancy outsourcing company that specialises in outsourcing for Accounting Practices.” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	96	32
8	Sapphire Info Solutions P LTDStrong evidence “Sapphire is an accounting outsourcing company set up for accounting firms in UK and is based in India.” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	88	28
9	Base Practice Support LTD Baseline Practice Support Smc-Pvt LTDIndirect evidence “Base Practice Support Ltd is the UK's fastest-growing Accountancy Practice Support company.” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	75	19
10	StellaripeIndirect evidence “We are on a mission to help accountants to grow their accountancy practice and become more profitable.” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	57	40
11	Artifin AccountantsPartial evidence “At Artifin Accountants we strive to provide a more open experience of accounting services for business owners.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	51	1
12	PSB Accountants LimitedIndirect evidence “At PSB Accountants, we put your goals and aspirations first.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	42	5
13	AscendantPartial evidence “Accounting.” Source: company website · checked Aug 30, 2026	London, United Kingdom	201-500	39	26
14	Glazers Chartered AccountantsIndirect evidence “Glazers is a well-established and progressive firm of accountants based in North West London.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	39	22
15	Complete Accounting SolutionsPartial evidence “Complete Accounting Solutions is a firm of dedicated individuals focussed on providing small and growing companies with support on the accounts and bookkeeping activities of their…” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	33	9
16	Bookcheck LTDIndirect evidence “Our clients rely on us to remove book-keeping hassle and improve their profitability by using our top quality financial reports based on professionally reconciled book-keeping.” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	29	24
17	Accnet Solutions LTDPartial evidence “AccNet Solutions was formed in November 2010 by Damitha Ukuwela as a firm providing accounting and bookkeeping solutions.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	20	9
18	Beatons GroupIndirect evidence “A consistently progressive approach to client service keeps the Beatons Group at the forefront of local and national business.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	19	17
19	ExcelsiousStrong evidence “Excelsious provides accounting, bookkeeping and finance function outsourcing services to accountancy firms and small to medium enterprises.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	17	3
20	BoobooksPartial evidence “Boobooks offers expert accounting, tax, and business support services tailored for small businesses.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	17	3
21	AAT Management ConsultantsIndirect evidence “WHY AAT?” Source: company website · checked Aug 30, 2026	London, United Kingdom	51-200	15	1
22	Asesa Solutions LTDIndirect evidence “With over 19 years of experience, ASESA Solutions Ltd offers world-class financial services, including comprehensive accounts management, precise bookkeeping, strategic HR…” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	15	1
23	BM Connect LimitedIndirect evidence “As specialist providers of outsourced bookkeeping, management accounts and payroll solutions, we work with clients spanning a range of sectors across the various stages of the…” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	14	10
24	Cfo360 UKIndirect evidence “55% of small businesses fail before their 5th birthday.” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	13	8
25	AMS Admin ServicesPartial evidence “AMS Admin Services: Accounting Made Simple At AMS Admin Services, we are dedicated to making accounting and financial management effortless and efficient for a wide array of…” Source: company website · checked Aug 30, 2026	London, United Kingdom	11-50	12	9

Showing 25 of 366 accounting outsourcing companies based in London, United Kingdom

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

As of Aug 30, 2026

1-10Median size (employees)

LondonLargest hub · 366 HQs

104Contacts with mobile numbers

Aug 30, 2026Data refreshed

Companies by employee count

1-10

241

11-50

51-200

201-500

501-1,000

1,001-5,000

Accounting outsourcing companies by metro in the United Kingdom

Metro	Companies
Accounting outsourcing companies in London	366
Accounting outsourcing companies in Manchester	36
Accounting outsourcing companies in Bristol	27
Accounting outsourcing companies in Birmingham	26
Accounting outsourcing companies in Glasgow	19
Accounting outsourcing companies in Leicester	18
Accounting outsourcing companies in Nottingham	16

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 accounting outsourcing companies, so some rows will be adjacent to the category rather than pure plays. The description and evidence rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
What qualifies: Companies headquartered in London, United Kingdom whose own description of what they do matches “accounting outsourcing companies”. Matching reads each company's description, not its industry code or its name.
What we exclude: Companies whose own description does not clearly place them among accounting outsourcing companies, 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 an evidence rating so you can judge each match yourself.
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, 985 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 August 30, 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.

Frequently asked

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

There are 366 accounting outsourcing companies 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 companies?

London leads with 366 headquartered companies, followed by Manchester (36) and Bristol (27).

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 985 verified decision-maker contacts tracked across these 366 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on August 30, 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.