Company lists · Data verified August 2026

Top 25 Advertising agencies based in London, United Kingdom

Name: Advertising agencies based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Verified Aug 28, 2026 2,236 companies tracked

There are 2,236 advertising agencies headquartered in London, United Kingdom (RevenueBase, August 2026). RevenueBase tracks 45,891 professional contacts across them, including 10,594 with verified work emails and 4,417 with mobile numbers. London is the largest hub.

This list covers advertising agencies headquartered in London, United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Data current as of August 28, 2026.

2,236Companies

45,891Contacts tracked

10,594Verified emails

4,417Mobile numbers

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The 25 largest advertising agencies based in London, United Kingdom

Ranked by team size

Top 25 of 2,236 advertising agencies based in London, United Kingdom, ranked by team size, largest first. Data verified Aug 28, 2026. Click a count to unlock that company's people.
#	Company	HQ	Employees	Contacts	Verified emails
1	CARAT	London	5,001-10,000	2,229	697
2	Omnicom Media Group UK	London	5,001-10,000	993	167
3	Anomaly	London	501-1,000	765	426
4	MG OMD	London	201-500	553	332
5	Mullenlowe Global	London	1,001-5,000	547	21
6	BBH London	London	201-500	518	204
7	OMD UK	London	201-500	475	284
8	Grapes Worldwide	London	201-500	396	74
9	Orion Worldwide	London	201-500	299	187
10	The7stars	London	201-500	296	196
11	Newbase	London	501-1,000	282	28
12	Forsman & Bodenfors	London	201-500	257	179
13	Amplify	London	201-500	180	123
14	Havas London	London	201-500	163	76
15	Grey London	London	201-500	158	69
16	Zenith	London	5,001-10,000	136	26
17	Zenith UK	London	201-500	133	12
18	METIA	London	201-500	131	44
19	The Mission Group	London	1,001-5,000	114	70
20	MSQ	London	1,001-5,000	113	65
21	Essencemediacomx	London	501-1,000	107	54
22	Konica Minolta Marketing Services	London	501-1,000	85	1
23	Unreasonable Studios	London	1,001-5,000	68	41
24	PEACH	London	201-500	46	22
25	Team ITG	London	1,001-5,000	41	20

Showing 25 of 2,236 advertising agencies based in London, United Kingdom

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Advertising agencies based in London, United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 2236 HQs

4,417Contacts with mobile numbers

66Emails re-verified in last 30 days

Companies by employee count

1-10

1,382

11-50

641

51-200

131

201-500

501-1,000

1,001-5,000

5,001-10,000

Advertising agencies by metro in the United Kingdom

Metro	Companies
Advertising agencies in London	2236
Advertising agencies in Manchester	216
Advertising agencies in Birmingham	115
Advertising agencies in Leeds	111
Advertising agencies in Bristol	77
Advertising agencies in Edinburgh	71
Advertising agencies in Glasgow	68

How this list was built

Source: The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion: Companies whose own business descriptions match “advertising agencies”, with match quality audited by blind human judging, and headquartered in London, United Kingdom.
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: Contact records re-verify on a rolling cadence; 66 contacts on this list were re-verified in the last 30 days.
Refresh: Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

How many advertising agencies are there based in London, United Kingdom?

There are 2,236 advertising agencies headquartered in London, United Kingdom as of August 2026 (RevenueBase).

What is the largest company on this list?

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

Which city has the most advertising agencies?

London leads with 2236 headquartered companies, followed by Manchester (216) and Birmingham (115).

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 10,594 verified decision-maker contacts tracked across these 2,236 companies.

How current is this list?

The list is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 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.