Company lists · Data refreshed September 2026

Top 25 Calling companies based in the United Kingdom

Name: Calling companies 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 870 companies tracked

RevenueBase identified 870 calling companies headquartered in the United Kingdom as of September 2026 and tracks 17,367 professional contacts across them, including 5,656 with verified work emails. London is the largest hub.

This list covers calling companies 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

870Companies

17,367Contacts tracked

5,656Verified emails

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The 25 largest calling companies based in the United Kingdom

Ranked by team size

Top 25 of 870 calling companies 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 calling companies: 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	Vodafone Business	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	10001+	6,767 contacts →
	Indirect evidence “Vodafone Business is part of the Vodafone Group.” Source: RevenueBase Database · checked Sep 21, 2026
2	GAMMA	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	1,568 contacts →
	Indirect evidence “Gamma Communications is a leading provider of technology-based communication solutions across Europe.” Source: RevenueBase Database · checked Sep 21, 2026
3	Onecom	Indirect evidence	Fareham, United KingdomHQ checked Sep 21, 2026	501-1,000	655 contacts →
	Indirect evidence “Onecom is the UK’s leading business telecoms and cloud communications provider managing over a million services for business customers - delivering communication services and…” Source: RevenueBase Database · checked Sep 21, 2026
4	4com	Indirect evidence	Bournemouth, United KingdomHQ checked Sep 21, 2026	501-1,000	358 contacts →
	Indirect evidence “Our Business Ethos: 4Com was founded in by our Chairman and MD, Daron Hutt with the aim of improving the communications services of the UK’s SME market.” Source: RevenueBase Database · checked Sep 21, 2026
5	Radius Connect Solutions	Indirect evidence	Crewe, United KingdomHQ checked Sep 21, 2026	201-500	122 contacts →
	Indirect evidence “Radius Connect Solutions is an award-winning independent “total communications” solution provider.” Source: RevenueBase Database · checked Sep 21, 2026
6	Tela Technology	Indirect evidence	Hampton-in-arden, United KingdomHQ checked Sep 21, 2026	51-200	111 contacts →
	Indirect evidence “We provide communication solutions and IT business services to businesses, big and small, to help your business grow.” Source: RevenueBase Database · checked Sep 21, 2026
7	YO Telecom	Indirect evidence	Southampton, United KingdomHQ checked Sep 21, 2026	51-200	97 contacts →
	Indirect evidence “Yo Telecom is an award winning telecommunications provider that specialises in small to medium sized businesses.” Source: RevenueBase Database · checked Sep 21, 2026
8	Bicom Systems	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	90 contacts →
	Indirect evidence “Made for businesses of all sizes, Bicom Systems revolutionizes communications by providing PBXware, the world's most unified turnkey open standards hosted telephony platform, plus…” Source: RevenueBase Database · checked Sep 21, 2026
9	Gradwell	Indirect evidence	Bath, United KingdomHQ checked Sep 21, 2026	51-200	85 contacts →
	Indirect evidence “Gradwell Communications Ltd are a leading cloud communications solutions provider with a focus on small to medium-sized businesses (SMEs).” Source: RevenueBase Database · checked Sep 21, 2026
10	Speedflow	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	79 contacts →
	Indirect evidence “With a broad experience in the industry, Speedflow is in the best position to provide you with products and services proven by time to be effective.” Source: RevenueBase Database · checked Sep 21, 2026
11	ICS Communications	Indirect evidence	Camberley, United KingdomHQ checked Sep 21, 2026	11-50	75 contacts →
	Indirect evidence “Contact an expert now: 0800 9 77 88 99 Specialists in providing businesses with telecoms, data and energy since 1989.” Source: RevenueBase Database · checked Sep 21, 2026
12	Rydal Group	Indirect evidence	Peterborough, United KingdomHQ checked Sep 21, 2026	51-200	74 contacts →
	Indirect evidence “Rydal Group is the brand name of Rydal Communications LTD, Rydal Security LTD & Rydal Energy LTD.” Source: RevenueBase Database · checked Sep 21, 2026
13	Welcomm Communications	Indirect evidence	Market Harborough, United KingdomHQ checked Sep 21, 2026	51-200	69 contacts →
	Indirect evidence “With 30+ years of experience in industry, Welcomm transform the way businesses communicate and operate.” Source: RevenueBase Database · checked Sep 21, 2026
14	Telappliant	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	67 contacts →
	Indirect evidence “Telappliant is an award-winning VoIP and cloud communications provider.” Source: RevenueBase Database · checked Sep 21, 2026
15	Britannic	Indirect evidence	Guildford, United KingdomHQ checked Sep 21, 2026	51-200	65 contacts →
	Indirect evidence “A leading Systems Integrator and Technology Innovator trusted by world class brands for over 40 years, Britannic designs, develops and delivers business communications, sovereign…” Source: RevenueBase Database · checked Sep 21, 2026
16	Enconvo UK	Indirect evidence	Telford, United KingdomHQ checked Sep 21, 2026	51-200	61 contacts →
	Indirect evidence “We’re a leading unified communications provider supplying over 2 million users with the technology they need to work their magic.” Source: RevenueBase Database · checked Sep 21, 2026
17	Abzorb	Indirect evidence	Brighouse, United KingdomHQ checked Sep 21, 2026	51-200	60 contacts →
	Indirect evidence “Business: It’s all about connecting people.” Source: RevenueBase Database · checked Sep 21, 2026
18	Firstcom Europe LTD	Indirect evidence	Bolton, United KingdomHQ checked Sep 21, 2026	51-200	56 contacts →
	Indirect evidence “We have over 20 years' experience of working to deliver best of breed cloud telephony solutions to B2B clients.” Source: RevenueBase Database · checked Sep 21, 2026
19	Cellular Solutions	Indirect evidence	Sunderland, United KingdomHQ checked Sep 21, 2026	n/a	56 contacts →
	Indirect evidence “Established in 1995, Cellular Solutions NE, now part of Communications Plus, is a trusted business telecoms provider supporting organisations across the North East and throughout…” Source: RevenueBase Database · checked Sep 21, 2026
20	Communications Plus Limited	Indirect evidence	Rainford, United KingdomHQ checked Sep 21, 2026	11-50	52 contacts →
	Indirect evidence “Communications Plus is an award-winning UK business telecoms provider, helping organisations across the UK improve the way they communicate, connect and work.” Source: RevenueBase Database · checked Sep 21, 2026
21	Citycom	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	46 contacts →
	Indirect evidence “Citycom is one of the UK’s leading providers of business telecoms solutions, offering mobile, fixed and cloud services.” Source: RevenueBase Database · checked Sep 21, 2026
22	Simplicity Group	Indirect evidence	Belfast, United KingdomHQ checked Sep 21, 2026	51-200	43 contacts →
	Indirect evidence “The Simplicity Group specialise in fully managed communications and technology solutions for businesses throughout the UK and Ireland.” Source: RevenueBase Database · checked Sep 21, 2026
23	XINIX	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	43 contacts →
	Indirect evidence “Xinix is UK’s leading cloud-based unified communication provider making persistent efforts towards modernizing business communications.” Source: RevenueBase Database · checked Sep 21, 2026
24	Forever Group	Indirect evidence	Kidderminster, United KingdomHQ checked Sep 21, 2026	n/a	37 contacts →
	Indirect evidence “Forever Group is a specialist provider of Business Telecommunications and IT solutions, based in Worcestershire.” Source: RevenueBase Database · checked Sep 21, 2026
25	Associated Telecom	Indirect evidence	Telford, United KingdomHQ checked Sep 21, 2026	11-50	34 contacts →
	Indirect evidence “We are an industry leading provider of Hosted Telephony, Mobile, IT and Connectivity solutions to businesses across the UK.” 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: calling companies. 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 calling companies.
Partial evidence: Its own public description names part of calling companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name calling companies. 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 870 calling companies based in the United Kingdom

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Calling companies based in the United Kingdom at a glance

As of Sep 21, 2026

32.6%Verified-email coverage

20.0Average contacts per company

1-10Median size (employees)

13.6%Largest-city concentration · London

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

453

11-50

339

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 870 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 calling companies, 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 “calling companies”. 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 calling companies), 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 calling companies, 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, 5,656 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.

Calling companies by metro

Calling companies in London118

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 calling companies, 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 calling companies are there based in the United Kingdom?

RevenueBase identified 870 calling companies 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?

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

Which city has the most calling companies?

London leads with 118 headquartered companies, followed by Manchester (22) and Birmingham (16).

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 5,656 verified decision-maker contacts tracked across these 870 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.