Company lists · Data refreshed September 2026

Top 25 Outsourcing for accounting firms based in the United Kingdom

Name: Outsourcing for accounting firms based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 3,190 companies tracked

RevenueBase identified 3,190 outsourcing for accounting firms headquartered in the United Kingdom as of September 2026 and tracks 18,653 professional contacts across them, including 4,745 with verified work emails. London is the largest hub.

This list covers outsourcing for accounting 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. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 21, 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 21, 2026 86% judged on-target in blind review

3,190Companies

18,653Contacts tracked

4,745Verified emails

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The 25 largest outsourcing for accounting firms based in the United Kingdom

Ranked by team size

Top 25 of 3,190 outsourcing for accounting firms based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to outsourcing for accounting firms: 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	Outbooks	Strong evidence	Harrow, United KingdomHQ checked Sep 21, 2026	201-500	477 contacts →
	Strong evidence “Outbooks is a leading provider of outsourcing services to accounting and bookkeeping firms.” Source: RevenueBase Database · checked Sep 21, 2026
2	Corient Business Solutions Limited	Partial evidence	Coventry, United KingdomHQ checked Sep 21, 2026	501-1,000	423 contacts →
	Partial evidence “Corient is a specialist outsourced accounting and bookkeeping partner, built exclusively for UK accountancy practices.” Source: RevenueBase Database · checked Sep 21, 2026
3	SKS Business Services	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	501-1,000	322 contacts →
	Indirect evidence “At SKS, we pride ourselves on being different.” Source: RevenueBase Database · checked Sep 21, 2026
4	GI Outsourcing	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	311 contacts →
	Partial evidence “GI Outsourcing is a UK-based accountants outsourcing firm.” Source: RevenueBase Database · checked Sep 21, 2026
5	Galloways Accounting	Partial evidence	Brighton, United KingdomHQ checked Sep 21, 2026	201-500	187 contacts →
	Partial evidence “Galloways is the fastest growing accounting services firm in Sussex.” Source: RevenueBase Database · checked Sep 21, 2026
6	Burgess Hodgson	Indirect evidence	Canterbury, United KingdomHQ checked Sep 21, 2026	51-200	140 contacts →
	Indirect evidence “Burgess Hodgson are a Kent based accountancy firm with the skills and expertise to rival any other accountancy firm in the UK.” Source: RevenueBase Database · checked Sep 21, 2026
7	Accounts And Legal	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	133 contacts →
	Indirect evidence “Traditional accountants do a great job of the numbers, but that's often as far as the service goes.” Source: RevenueBase Database · checked Sep 21, 2026
8	Intelligent Outsourcing	Strong evidence	Tunbridge Wells, United KingdomHQ checked Sep 21, 2026	51-200	118 contacts →
	Strong evidence “Intelligent Outsourcing (iO) is an offshoring company in the Philippines dedicated to supporting UK accounting practices.” Source: RevenueBase Database · checked Sep 21, 2026
9	Initor Global UK	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	108 contacts →
	Indirect 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: RevenueBase Database · checked Sep 21, 2026
10	FLB Accountants LLP	Partial evidence	Wokingham, United KingdomHQ checked Sep 21, 2026	51-200	107 contacts →
	Partial evidence “FLB is a firm of accountants providing core accounting services to a range of clients from start-ups, owner-managed businesses and private clients, to large corporates and…” Source: RevenueBase Database · checked Sep 21, 2026
11	Debitam	Partial evidence	42-44 Bishopsgate, United KingdomHQ checked Sep 21, 2026	51-200	104 contacts →
	Partial 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: RevenueBase Database · checked Sep 21, 2026
12	SJD Accountancy	Indirect evidence	Hemel Hempstead, United KingdomHQ checked Sep 21, 2026	501-1,000	102 contacts →
	Indirect evidence “SJD is now Caroola Accountancy!” Source: RevenueBase Database · checked Sep 21, 2026
13	Rayner Essex LLP	Indirect evidence	St Albans, United KingdomHQ checked Sep 21, 2026	51-200	98 contacts →
	Indirect evidence “At Rayner Essex, we believe your accountant should do a lot more than just report on how your business is doing - he or she should help you identify opportunities to improve your…” Source: RevenueBase Database · checked Sep 21, 2026
14	Affinity Outsourcing Limited	Strong evidence	Wembley, United KingdomHQ checked Sep 21, 2026	51-200	96 contacts →
	Strong evidence “Affinity Outsourcing is an accountancy outsourcing company that specialises in outsourcing for Accounting Practices.” Source: RevenueBase Database · checked Sep 21, 2026
15	Sapphire Info Solutions P LTD	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	88 contacts →
	Strong evidence “Sapphire is an accounting outsourcing company set up for accounting firms in UK and is based in India.” Source: RevenueBase Database · checked Sep 21, 2026
16	Base Practice Support LTD Baseline Practice Support Smc-Pvt LTD	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	78 contacts →
	Indirect evidence “Base Practice Support Ltd is the UK's fastest-growing Accountancy Practice Support company.” Source: RevenueBase Database · checked Sep 21, 2026
17	Affinity Associates Limited	Partial evidence	Wembley, United KingdomHQ checked Sep 21, 2026	201-500	64 contacts →
	Partial evidence “Affinity Associates Limited is a leading accounting firm based in Wembley, London, UK, and is regulated and authorised for public practice by both the ICAEW (Institute of…” Source: RevenueBase Database · checked Sep 21, 2026
18	The Accountancy Partnership	Partial evidence	Wirral, United KingdomHQ checked Sep 21, 2026	51-200	62 contacts →
	Partial evidence “We offer online accounting services which simplify tax and finances for small businesses, by providing a fresh alternative to old-school high street accountants.” Source: RevenueBase Database · checked Sep 21, 2026
19	Greybeard Automation & Outsourcing	Strong evidence	Brighouse, United KingdomHQ checked Sep 21, 2026	11-50	62 contacts →
	Strong evidence “Greybeard Solutions provides expert accounting outsourcing and business process automation services to SMEs worldwide.” Source: RevenueBase Database · checked Sep 21, 2026
20	Stellaripe	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	58 contacts →
	Indirect evidence “We are on a mission to help accountants to grow their accountancy practice and become more profitable.” Source: RevenueBase Database · checked Sep 21, 2026
21	Acenteus Accounting	Partial evidence	Plus X Innovation, United KingdomHQ checked Sep 21, 2026	51-200	56 contacts →
	Partial evidence “Acenteus Accounting, legally known as Acenteus CCA Global Ltd is a UK-registered outsourced accounting and finance partner delivering secure, cloud-enabled support for…” Source: RevenueBase Database · checked Sep 21, 2026
22	DSL Accounting	Indirect evidence	Leamington Spa, United KingdomHQ checked Sep 21, 2026	n/a	54 contacts →
	Indirect evidence “DSL is one of the UK's leading small business accountancy firms, helping businesses grow since 1997.” Source: RevenueBase Database · checked Sep 21, 2026
23	Adler Shine	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	53 contacts →
	Indirect evidence “Est.” Source: RevenueBase Database · checked Sep 21, 2026
24	Artifin Accountants	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	53 contacts →
	Partial evidence “At Artifin Accountants we strive to provide a more open experience of accounting services for business owners.” Source: RevenueBase Database · checked Sep 21, 2026
25	MIMO	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	52 contacts →
	Partial evidence “Mimo fixes accounting delivery by automating repetitive work and removing the admin that slows firms down, so accountants can focus on advisory and clients can get clarity when it…” Source: RevenueBase Database · checked Sep 21, 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: outsourcing for accounting firms. 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 outsourcing for accounting firms.
Partial evidence: Its own public description names part of outsourcing for accounting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name outsourcing for accounting firms. 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 25 of 3,190 outsourcing for accounting firms based in the United Kingdom

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Outsourcing for accounting firms based in the United Kingdom at a glance

As of Sep 21, 2026

25.4%Verified-email coverage

5.8Average contacts per company

1-10Median size (employees)

18.2%Largest-city concentration · London

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

2,564

11-50

490

51-200

201-500

501-1,000

1,001-5,000

Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 3,190 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 outsourcing for accounting firms, 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 the United Kingdom whose own description of what they do matches “outsourcing for accounting firms”. 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 outsourcing for accounting firms), 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 outsourcing for accounting firms, and records with no verified work email. Companies headquartered outside United Kingdom 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, 4,745 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 21, 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.

Outsourcing for accounting firms by metro

Outsourcing for accounting firms in London579
Outsourcing for accounting firms in Manchester59
Outsourcing for accounting firms in Bristol43
Outsourcing for accounting firms in Birmingham39
Outsourcing for accounting firms in Glasgow28
Outsourcing for accounting firms in Leeds28
Outsourcing for accounting firms in Nottingham27

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 outsourcing for accounting firms, 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 outsourcing for accounting firms are there based in the United Kingdom?

RevenueBase identified 3,190 outsourcing for accounting firms headquartered in the 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?

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

Which city has the most outsourcing for accounting firms?

London leads with 579 headquartered companies, followed by Manchester (59) and Bristol (43).

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 4,745 verified decision-maker contacts tracked across these 3,190 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 21, 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.