Company lists · Data refreshed September 2026
Top 25 Sales call centers based in the United Kingdom
RevenueBase identified 229 sales call centers headquartered in the United Kingdom as of September 2026 and tracks 3,499 professional contacts across them, including 723 with verified work emails. London is the largest hub.
This list covers sales call centers 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 29, 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.
The 25 largest sales call centers based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 490 contacts → | ||||
Indirect evidence “Give your customers a voice with ResQ.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 243 contacts → | ||||
Partial evidence “The Telemarketing Company is one of the UK's most trusted telemarketing agencies, delivering flexible, high-quality voice services, including pre and post sales research…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 205 contacts → | ||||
Indirect evidence “Established since 1998 Clearanswer is an expert provider of contact centre solutions.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 132 contacts → | ||||
Indirect evidence “Dedicated and shared contact centre outsourcing operations.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 119 contacts → | ||||
Indirect evidence “GCL, with its unique, non-scripted approach to telemarketing and related marketing services, has for over 30 years established an enviable reputation for providing winning lead…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 116 contacts → | ||||
Partial evidence “Since 2016, Air Marketing has been the trusted outsourced sales and lead generation agency in the UK for ambitious B2B businesses.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 7 | 114 contacts → | ||||
Indirect evidence “EC Outsourcing is one of the UK's leading outsourced contact centres.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 112 contacts → | ||||
Indirect evidence “Step Change Outsourcing is a growing contact centre working in partnership with some of the UK’s largest brands for over 15 years.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 82 contacts → | ||||
Partial evidence “Alliance Sales Support Services provides effective and sustainable sales solutions for your business.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 10 | 75 contacts → | ||||
Indirect evidence “Voice is an agency that specialises in customer acquisition, development and retention programs.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 59 contacts → | ||||
Partial evidence “Looking to fill your calendar with qualified calls?” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 57 contacts → | ||||
Indirect evidence “At Contact Web, we deliver customer experience outsourcing differently.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 54 contacts → | ||||
Strong evidence “We are an established AI-enabled call centre specialising in every aspect of sales and customer service.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 14 | 47 contacts → | ||||
Indirect evidence “4Marketing is a direct marketing agency devoted to generating new business opportunities for its clients through its focused new generation of telemarketing professionals.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 15 | 45 contacts → | ||||
Indirect evidence “Advance Connects are a B2B telemarketing, lead generation & appointment scheduling experts, operating within various sectors including construction, built environment, industrial…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 43 contacts → | ||||
Indirect evidence “Beanstalk is an integrated B2B Telemarketing and Lead Generation agency dedicated to helping our customers win new business.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 43 contacts → | ||||
Indirect evidence “B2B and B2C outsourced Telemarketing agency.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 39 contacts → | ||||
Partial evidence “For over 20 years, Chase Response has delivered unrivalled standards in call centre outsourcing and customer management services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 19 | 37 contacts → | ||||
Indirect evidence “Founded in 2002, eContact Services is a telemarketing agency specializing in lead generation and appointment setting for communication service providers-fixed and mobile…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 35 contacts → | ||||
Partial evidence “1 Stop Data offers the best of breed Marketing, Lead Generation and Call Centre services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 21 | 32 contacts → | ||||
Indirect evidence “Telu is the complete business solution for generating leads and revenue for your business.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 22 | 31 contacts → | ||||
Indirect evidence “IT Focus Telemarketing Ltd is an agency that specialises in working with information technology companies.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 27 contacts → | ||||
Indirect evidence “Since SLM Connect started up as a contact centre in 2008, we've supplied more than customers to our clients.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 24 | 22 contacts → | ||||
Indirect evidence “Helping you develop a customer-focused business.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 25 | 16 contacts → | ||||
Partial evidence “Newton Fox are a UK-based B2B telemarketing and lead generation specialist with over 17 years of experience helping ambitious businesses fill their sales pipelines.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
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: sales call centers. 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 sales call centers.
- Partial evidence
- Its own public description names part of sales call centers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name sales call centers. 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 229 sales call centers based in the United Kingdom
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Sales call centers based in the United Kingdom at a glance
As of Sep 29, 2026Companies by employee count
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 229 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 sales call centers, 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 “sales call centers”. 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 sales call centers), 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 sales call centers, 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, 723 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 29, 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 sales call centers, 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 sales call centers are there based in the United Kingdom?
RevenueBase identified 229 sales call centers 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?
RESQ, headquartered in Kingston Upon Hull, tops this list with the largest team on record.
Which city has the most sales call centers?
London leads with 39 headquartered companies, followed by Manchester (8) and Leeds (7).
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 723 verified decision-maker contacts tracked across these 229 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 29, 2026.
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- Sales call centers based in Mexico
- Sales call centers based in the Netherlands
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- Sales call centers based in Poland
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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.