Company lists · Data refreshed September 2026

Top 25 Outsourced accounting bookkeeping firms based in the United Kingdom

RevenueBase identified 4,157 outsourced accounting bookkeeping firms headquartered in the United Kingdom as of September 2026 and tracks 20,649 professional contacts across them, including 5,096 with verified work emails. London is the largest hub.

This list covers outsourced accounting bookkeeping 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
4,157Companies
20,649Contacts tracked
5,096Verified emails
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The 25 largest outsourced accounting bookkeeping firms based in the United Kingdom

Ranked by team size
Top 25 of 4,157 outsourced accounting bookkeeping 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 outsourced accounting bookkeeping 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Strong evidenceHarrow, United KingdomHQ checked Sep 21, 2026201-500477 contacts →

Strong evidence

“Outbooks is a leading provider of outsourcing services to accounting and bookkeeping firms.”

Source: RevenueBase Database · checked Sep 21, 2026
2Strong evidenceCoventry, United KingdomHQ checked Sep 21, 2026501-1,000423 contacts →

Strong evidence

“Corient is a specialist outsourced accounting and bookkeeping partner, built exclusively for UK accountancy practices.”

Source: RevenueBase Database · checked Sep 21, 2026
3Indirect evidenceCanterbury, United KingdomHQ checked Sep 21, 202651-200140 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
4Indirect evidenceNewport, United KingdomHQ checked Sep 21, 202651-200134 contacts →

Indirect evidence

“Award winning accountants & tax advisors based in Newport, South Wales.”

Source: RevenueBase Database · checked Sep 21, 2026
5Indirect evidenceLondon, United KingdomHQ checked Sep 21, 202611-50133 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
6Indirect evidenceLondon, United KingdomHQ checked Sep 21, 202651-200108 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
7Strong evidence42-44 Bishopsgate, United KingdomHQ checked Sep 21, 202651-200104 contacts →

Strong 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
8Indirect evidenceLondon, United KingdomHQ checked Sep 21, 2026501-1,000100 contacts →

Indirect evidence

“Paperchase Business Services Ltd (PBSL) is a firm of accountants, taxation and business advisors based in South London.”

Source: RevenueBase Database · checked Sep 21, 2026
9Indirect evidenceSt Albans, United KingdomHQ checked Sep 21, 202651-20098 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
10Strong evidenceWembley, United KingdomHQ checked Sep 21, 202651-20096 contacts →

Strong evidence

“Affinity Outsourcing is an accountancy outsourcing company that specialises in outsourcing for Accounting Practices.”

Source: RevenueBase Database · checked Sep 21, 2026
11Strong evidenceLondon, United KingdomHQ checked Sep 21, 202651-20088 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
12Partial evidenceWembley, United KingdomHQ checked Sep 21, 2026201-50064 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
13Indirect evidenceChiswick Park, United KingdomHQ checked Sep 21, 202611-5063 contacts →

Indirect evidence

“At Oasis Accountants we make sure to keep your business profitable.”

Source: RevenueBase Database · checked Sep 21, 2026
14Partial evidenceLondon, United KingdomHQ checked Sep 21, 202651-20063 contacts →

Partial evidence

“ARNA Accounting Pvt Limited is expert in FinTech.”

Source: RevenueBase Database · checked Sep 21, 2026
15Partial evidenceWirral, United KingdomHQ checked Sep 21, 202651-20062 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
16Strong evidenceBrighouse, United KingdomHQ checked Sep 21, 202611-5062 contacts →

Strong evidence

“Greybeard Solutions provides expert accounting outsourcing and business process automation services to SMEs worldwide.”

Source: RevenueBase Database · checked Sep 21, 2026
17Indirect evidencePortsmouth, United KingdomHQ checked Sep 21, 202651-20060 contacts →

Indirect evidence

“If you’re looking for clear, practical financial advice tailored to your needs, you’re in the right place.”

Source: RevenueBase Database · checked Sep 21, 2026
18Indirect evidenceLondon, United KingdomHQ checked Sep 21, 202651-20058 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
19Strong evidencePlus X Innovation, United KingdomHQ checked Sep 21, 202651-20056 contacts →

Strong 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
20Indirect evidenceLeamington Spa, United KingdomHQ checked Sep 21, 2026n/a54 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
21Partial evidenceLondon, United KingdomHQ checked Sep 21, 202611-5053 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
22Indirect evidenceLondon, United KingdomHQ checked Sep 21, 202611-5051 contacts →

Indirect evidence

“We’ve been around for a while now, celebrating our 50th anniversary in 2020.”

Source: RevenueBase Database · checked Sep 21, 2026
23Indirect evidenceLondon, United KingdomHQ checked Sep 21, 202611-5051 contacts →

Indirect evidence

“Empowering Businesses to Thrive Through Financial Clarity | Adroit Accountax We're a team of passionate and experienced accountants dedicated to your business success.”

Source: RevenueBase Database · checked Sep 21, 2026
24Indirect evidenceReading, United KingdomHQ checked Sep 21, 202611-5048 contacts →

Indirect evidence

“We help reduce your stress and deal with all your company accounts and advice We handle all your payroll requirements We deal with your tax returns and pension requirements You…”

Source: RevenueBase Database · checked Sep 21, 2026
25Indirect evidenceCorby, United KingdomHQ checked Sep 21, 202651-20047 contacts →

Indirect evidence

“At Moore, our purpose is to help people thrive – our clients, our people and the communities they live and work in.”

Source: RevenueBase Database · checked Sep 21, 2026

Showing 25 of 4,157 outsourced accounting bookkeeping firms based in the United Kingdom

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Outsourced accounting bookkeeping firms based in the United Kingdom at a glance

As of Sep 21, 2026
24.7%Verified-email coverage
5.0Average contacts per company
1-10Median size (employees)
17.8%Largest-city concentration · London
Sep 21, 2026Page data refreshed

Companies by employee count

1-10
3,401
11-50
614
51-200
67
201-500
17
501-1,000
5
1,001-5,000
4

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 4,157 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 outsourced accounting bookkeeping 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 “outsourced accounting bookkeeping 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 outsourced accounting bookkeeping 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 outsourced accounting bookkeeping 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, 5,096 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.

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 outsourced accounting bookkeeping 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 outsourced accounting bookkeeping firms are there based in the United Kingdom?

RevenueBase identified 4,157 outsourced accounting bookkeeping 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 outsourced accounting bookkeeping firms?

London leads with 741 headquartered companies, followed by Manchester (85) and Bristol (52).

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 5,096 verified decision-maker contacts tracked across these 4,157 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.