Company lists · Data refreshed September 2026

Top 25 Professional services outsourcing firms based in London, United Kingdom

RevenueBase identified 205 company matches for professional services outsourcing firms associated with London, United Kingdom as of September 2026 and tracks 3,270 professional contacts across them, including 886 with verified work emails. Across the United Kingdom, London is the largest hub for this category.

This list covers company matches for professional services outsourcing firms associated with London, United Kingdom, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed September 29, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase SmartSearch, 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 RevenueBase SmartSearch · Exact Recorded Sep 29, 2026 How this list was built
205Companies
3,270Contacts tracked
886Verified emails
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The 25 largest professional services outsourcing firms based in London, United Kingdom

Ranked by team size
Top 25 of 205 company matches for professional services outsourcing firms based in London, United Kingdom, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 29, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#CompanyRevenueBase SmartSearchHeadquartersEmployeesContacts
1Exact matchLondon, United KingdomHQ recorded Sep 29, 2026501-1,000333 contacts →

Exact match

“Ubique Systems is a fast growing multifaceted organization which offers a comprehensive array of outsourcing and consulting services for its customers, including recruitment…”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
2Exact matchLondon, United KingdomHQ recorded Sep 29, 2026501-1,000322 contacts →

Exact match

“At SKS, we pride ourselves on being different.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
3Exact matchLondon, United KingdomHQ recorded Sep 29, 2026201-500311 contacts →

Exact match

“GI Outsourcing is a UK-based accountants outsourcing firm.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
4Exact matchLondon, United KingdomHQ recorded Sep 29, 202651-200108 contacts →

Exact match

“As attention turns to the new fiscal year, accountants across the UK are finalising plans to boost growth and productivity and improve profitability.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
5Exact matchLondon, United KingdomHQ recorded Sep 29, 202651-20088 contacts →

Exact match

“Founded in 2001 by lawyers, Global BPO provides bespoke legal and business services to law firms, professional service organisations and other businesses.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
6Exact matchLondon, United KingdomHQ recorded Sep 29, 2026201-50070 contacts →

Exact match

“We are a 400 member strong, specialist business process outsourcing (BPO) provider that caters to the diverse and complex information processing needs of todays corporation.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
7Exact matchLondon, United KingdomHQ recorded Sep 29, 202651-20042 contacts →

Exact match

“Diacron Group provides accounting, tax and corporate services.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
8Exact matchLondon, United KingdomHQ recorded Sep 29, 202651-20041 contacts →

Exact match

“Welcome to Factotum-your secret weapon for streamlined business success!”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
9Exact matchLondon, United KingdomHQ recorded Sep 29, 2026201-50037 contacts →

Exact match

“Charles Marcus is our multinational network of consultancy firms.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
10Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5027 contacts →

Exact match

“WTS Hansuke is a specialist professional services firm notable for its focus on excellent client service and agility.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
11Exact matchLondon, United KingdomHQ recorded Sep 29, 202651-20027 contacts →

Exact match

“Now part of the Lawyers on Demand offering within the broader Consilio family.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
12Exact matchLondon, United KingdomHQ recorded Sep 29, 202651-20026 contacts →

Exact match

“KBM Group was founded as a Chartered Certified Accountancy firm, offering advisory and consulting services for business start-ups and organizations looking to strengthen their…”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
13Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5024 contacts →

Exact match

“Oakford Advisors Ltd, a Centralis Group company, is an outsourced business services firm which specialises in providing back-office support to start-up or existing companies…”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
14Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5022 contacts →

Exact match

“What we do We are a specialist professional services firm providing consulting and assurance services, particularly to the Financial Services sector.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
15Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5018 contacts →

Exact match

“Established in 2006, 3Kites is a consultancy that provides the professional services sector with fresh thinking based on its unique combination of legal and IT skills and…”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
16Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5018 contacts →

Exact match

“We solve complex problems from starting up to exit providing robust, tax compliant and cost-effective solutions that adapt and scale, always tailored to your needs.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
17Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5017 contacts →

Exact match

“Chartered Solutions allows Professional Services firms to take on additional work without the added risk and responsibilities of hiring permanent employees.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
18Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5017 contacts →

Exact match

“We are The Professional Services Advisory Firm.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
19Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5016 contacts →

Exact match

“Supporting professional services firms with their requirements across setup, adoption, data migration, training, managed services and integrations.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
20Exact matchLondon, United KingdomHQ recorded Sep 29, 202651-20016 contacts →

Exact match

“Burcher Jennings offer a comprehensive portfolio of specialist services tailored exclusively to the needs of modern law firms.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
21Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5014 contacts →

Exact match

“We partner with businesses when they don't have the time or resources to do everything themselves.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
22Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5012 contacts →

Exact match

“At Chariot House, we specialize in supporting small to medium-sized organisations in managing their finances more efficiently and with greater simplicity.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
23Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-5012 contacts →

Exact match

“We bring our extensive industry experience to the hum-drum of finance, HR, operations, marketing and compliance so that you can focus on delivering the fun to your customers.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
24Exact matchLondon, United KingdomHQ recorded Sep 29, 20261-1011 contacts →

Exact match

“About AnyBPO: AnyBPO is an international consulting company specializing in Business Process Outsourcing (BPO) solutions.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase
25Exact matchLondon, United KingdomHQ recorded Sep 29, 202611-508 contacts →

Exact match

“We are a consultancy-led professional services firm helping businesses evolve through insight, execution, and technology.”

Recorded in the RevenueBase company graph · Sep 29, 2026 · View company records in RevenueBase

Showing 25 of 205 professional services outsourcing firms based in London, United Kingdom

See the full list, filter by size, metro and specialty, and access 886 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Professional services outsourcing firms based in London, United Kingdom at a glance

As of Sep 29, 2026
27.1%Verified-email coverage
16.0Average contacts per company
1-10Median size (employees)
Sep 29, 2026Page data refreshed

Companies by employee count

1-10
104
11-50
62
51-200
24
201-500
8
501-1,000
6
1,001-5,000
1

Email recency for this list is measured across the whole United Kingdom list rather than for London, so it is reported there. Company counts and contact totals on this page are exact for London, over 205 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies
Company records associated with London, United Kingdom whose business descriptions match “professional services outsourcing firms” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch
Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview
The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality
RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
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 displayed company carries at least one verified work email. RevenueBase tracks 886 professional contacts with verified work emails across the full matched dataset. 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 29, 2026. Lists refresh periodically as the graph is re-checked.
Record context
Company records and descriptions can change. Check the company's website for its current services and locations.

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “professional services outsourcing firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

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

RevenueBase identified 205 company matches for professional services outsourcing firms associated with London, United Kingdom as of September 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

Ubique Systems tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city in the United Kingdom has the most professional services outsourcing firms?

London leads the United Kingdom with 205 company records, followed by Manchester (17) and Birmingham (10).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 886 professional contacts with verified work emails tracked across these 205 companies; direct dials are available where recorded.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 29, 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 SmartSearch, 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.