Company lists · Data refreshed September 2026

Top 25 Human resources outsourcing firms based in the United Kingdom

Name: Human resources outsourcing 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 28, 2026 1,552 companies tracked

RevenueBase identified 1,552 human resources outsourcing firms headquartered in the United Kingdom as of September 2026 and tracks 12,710 professional contacts across them, including 4,091 with verified work emails. London is the largest hub.

This list covers human resources 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. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 28, 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 28, 2026 86% judged on-target in blind review

1,552Companies

12,710Contacts tracked

4,091Verified emails

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest human resources outsourcing firms based in the United Kingdom

Ranked by team size

Top 25 of 1,552 human resources outsourcing firms based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to human resources outsourcing 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	NGA Human Resources, An Alight Company	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	1,001-5,000	2,734 contacts →
	Strong evidence “At Alight \| NGA Human Resources our mission is to make HR work better.” Source: RevenueBase Database · checked Sep 28, 2026
2	Zellis	Indirect evidence	Bristol, United KingdomHQ checked Sep 28, 2026	1,001-5,000	1,465 contacts →
	Indirect evidence “Zellis helps organisations unlock better outcomes by creating exceptional experiences for their people.” Source: RevenueBase Database · checked Sep 28, 2026
3	Croner	Indirect evidence	Wheatfield Way, United KingdomHQ checked Sep 28, 2026	201-500	400 contacts →
	Indirect evidence “Our award winning HR and health & safety services free you from workforce admin and help keep you on the right side of the law.” Source: RevenueBase Database · checked Sep 28, 2026
4	Ubique Systems	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	501-1,000	333 contacts →
	Partial evidence “Ubique Systems is a fast growing multifaceted organization which offers a comprehensive array of outsourcing and consulting services for its customers, including recruitment…” Source: RevenueBase Database · checked Sep 28, 2026
5	GI Outsourcing	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	201-500	311 contacts →
	Partial evidence “GI Outsourcing is a UK-based accountants outsourcing firm.” Source: RevenueBase Database · checked Sep 28, 2026
6	Omni RMS	Indirect evidence	Altrincham, United KingdomHQ checked Sep 28, 2026	51-200	190 contacts →
	Indirect evidence “Omni – Talent Is Everything At Omni, we help businesses find, attract, and retain the right people to drive long-term success.” Source: RevenueBase Database · checked Sep 28, 2026
7	The HR Dept	Indirect evidence	Bristol, United KingdomHQ checked Sep 28, 2026	51-200	169 contacts →
	Indirect evidence “Welcome to The HR Dept.” Source: RevenueBase Database · checked Sep 28, 2026
8	Cintra HR & Payroll Services	Indirect evidence	Newcastle Upon Tyne, United KingdomHQ checked Sep 28, 2026	51-200	148 contacts →
	Indirect evidence “Proudly based in the North East, our multi award-winning Payroll & HR service has been delivering professional payroll and HR solutions for over 40 years.” Source: RevenueBase Database · checked Sep 28, 2026
9	Lace Partners	Indirect evidence	South Bank, United KingdomHQ checked Sep 28, 2026	51-200	129 contacts →
	Indirect evidence “Overview LACE Partners is trusted advisors to HR and business leaders navigating complex workforce challenges.” Source: RevenueBase Database · checked Sep 28, 2026
10	Avensure LTD	Indirect evidence	Manchester, United KingdomHQ checked Sep 28, 2026	51-200	127 contacts →
	Indirect evidence “Avensure provides UK businesses with bespoke outsourced HR, Employment Law, and Health & Safety services, built around the principle that protection is personal.” Source: RevenueBase Database · checked Sep 28, 2026
11	Talent Solutions UK	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	1,001-5,000	120 contacts →
	Indirect evidence “Talent Solutions combines ManpowerGroup's leading global offerings RPO, TAPFIN-MSP and Right Management to provide end-to-end, data-driven capabilities across the talent lifecycle.” Source: RevenueBase Database · checked Sep 28, 2026
12	People Puzzles	Indirect evidence	Duxford, United KingdomHQ checked Sep 28, 2026	51-200	116 contacts →
	Indirect evidence “Better people, better business, better life.” Source: RevenueBase Database · checked Sep 28, 2026
13	NES Advantage Managed Services, Rpo, EOR Staffing Services	Indirect evidence	Manchester, United KingdomHQ checked Sep 28, 2026	1,001-5,000	99 contacts →
	Indirect evidence “We’ve got a lot to offer our customers; global reach, local expertise, bags of commitment and a huge degree of flexibility and know-how.” Source: RevenueBase Database · checked Sep 28, 2026
14	Sampeople	Indirect evidence	Calder Grove, United KingdomHQ checked Sep 28, 2026	51-200	74 contacts →
	Indirect evidence “SAMpeople, SAMpeople Recruit and SAMpeople Payroll” Source: RevenueBase Database · checked Sep 28, 2026
15	Payescape LTD	Indirect evidence	Northern Ireland, United KingdomHQ checked Sep 28, 2026	51-200	67 contacts →
	Indirect evidence “PayEscape is one of the UK’s fastest growing outsourced Payroll, HR and Time Management providers.” Source: RevenueBase Database · checked Sep 28, 2026
16	Everett SKY	Indirect evidence	Essex, United KingdomHQ checked Sep 28, 2026	51-200	61 contacts →
	Indirect evidence “Based in Europe, Everett Sky specializes in helping businesses scale their teams for growth through transformative solutions and exceptional customer service.” Source: RevenueBase Database · checked Sep 28, 2026
17	Cogito	Indirect evidence	Bristol, United KingdomHQ checked Sep 28, 2026	11-50	61 contacts →
	Indirect evidence “Working with business leaders and HR teams to transform people strategies, HR and Recruitment teams and deliver improved Return on Investment across the entire employee lifecycle.” Source: RevenueBase Database · checked Sep 28, 2026
18	Oakleaf Partnership	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	57 contacts →
	Indirect evidence “Since 2005, Oakleaf Partnership has been successfully placing people into jobs across every HR discipline, in every sector imaginable.” Source: RevenueBase Database · checked Sep 28, 2026
19	Hunter Adams	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	53 contacts →
	Indirect evidence “Hunter Adams is an employee-owned HR consultancy, Interim and recruitment business.” Source: RevenueBase Database · checked Sep 28, 2026
20	Warriorz Technologies	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	201-500	51 contacts →
	Strong evidence “In a highly technical industry of Information Technology, Warriorz Technologies Ltd is paving the way in Human Resource and Software consulting across the globe.” Source: RevenueBase Database · checked Sep 28, 2026
21	Randstad UK	Indirect evidence	Luton, United KingdomHQ checked Sep 28, 2026	1,001-5,000	51 contacts →
	Indirect evidence “Randstad is the world's largest HR services provider and is driven to become the world's most valued 'working life partner', supporting people all over the world to find their…” Source: RevenueBase Database · checked Sep 28, 2026
22	Industry Resource Services IRS Group	Indirect evidence	Beccles, United KingdomHQ checked Sep 28, 2026	11-50	47 contacts →
	Indirect evidence “Leading providers of specialist support services.” Source: RevenueBase Database · checked Sep 28, 2026
23	Project Recruit	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	45 contacts →
	Indirect evidence “At Project Recruit, getting to know our clients is at the heart of what we do.” Source: RevenueBase Database · checked Sep 28, 2026
24	Factotum	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	41 contacts →
	Indirect evidence “Welcome to Factotum-your secret weapon for streamlined business success!” Source: RevenueBase Database · checked Sep 28, 2026
25	Datum RPO	Partial evidence	Stonehouse, United KingdomHQ checked Sep 28, 2026	11-50	41 contacts →
	Partial evidence “Datum RPO are experts in procuring and managing Contingent Workforce Solutions (CWS) and Permanent Workforce Solutions (PWS) and provide a complete Recruitment Process Outsourcing…” Source: RevenueBase Database · checked Sep 28, 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: human resources outsourcing 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 human resources outsourcing firms.
Partial evidence: Its own public description names part of human resources outsourcing firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name human resources outsourcing 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 1,552 human resources outsourcing firms based in the United Kingdom

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 4,091 reachable decision-makers.

Free signup · no credit card

View the full list →

Human resources outsourcing firms based in the United Kingdom at a glance

As of Sep 28, 2026

32.2%Verified-email coverage

8.2Average contacts per company

1-10Median size (employees)

23.0%Largest-city concentration · London

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

1,252

11-50

220

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

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 1,552 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 human resources outsourcing 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 “human resources outsourcing 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 human resources outsourcing 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 human resources outsourcing 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, 4,091 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 28, 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.

Human resources outsourcing firms by metro

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 human resources outsourcing 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 human resources outsourcing firms are there based in the United Kingdom?

RevenueBase identified 1,552 human resources outsourcing 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?

NGA Human Resources, An Alight Company, headquartered in London, tops this list with the largest team on record.

Which city has the most human resources outsourcing firms?

London leads with 357 headquartered companies, followed by Manchester (37) and Bristol (23).

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 4,091 verified decision-maker contacts tracked across these 1,552 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 28, 2026.

Ready to reach these companies? Verified emails and direct dials for all 1,552 human resources outsourcing firms based in the United Kingdom. Start with a free account, no credit card.

Download this list →

Related lists

Human resources outsourcing firms by geography

Browse the directory

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.