Company lists · Data refreshed September 2026
Top 25 Ucaas providers based in the United Kingdom
RevenueBase identified 258 ucaas providers headquartered in the United Kingdom as of September 2026 and tracks 4,329 professional contacts across them, including 1,472 with verified work emails. London is the largest hub.
This list covers ucaas providers 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 22, 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 ucaas providers based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 2 | 120 contacts → | ||||
Indirect evidence “The Collaboration and CX solutions offered by NTT Ltd.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 3 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 4 | 86 contacts → | ||||
Indirect evidence “Sipcom exists to make you the hero of your business narrative by turning complexity into clarity.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 5 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 6 | 67 contacts → | ||||
Indirect evidence “Telappliant is an award-winning VoIP and cloud communications provider.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 7 | 62 contacts → | ||||
Indirect evidence “Nebula is a leading SaaS provider of workplace communications software, delivering powerful, secure, and adaptable solutions and applications for voice, messaging, customer…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 8 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 9 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 10 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 11 | 45 contacts → | ||||
Indirect evidence “Microtalk: Global Communications Made Simple For over 15 years, Microtalk has delivered reliable voice, messaging, and cloud communications to businesses worldwide.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 12 | 43 contacts → | ||||
Indirect evidence “Voiceflex is an innovative and multi-award-winning wholesale communications provider and leading telecoms carrier of SIP, Hosted Telephony, Connectivity, Unified Communications…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 13 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 14 | 36 contacts → | ||||
Indirect evidence “Zest4 are a leading provider of Unified Communications solutions for resellers across the UK.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 15 | 36 contacts → | ||||
Indirect evidence “As the UK and Ireland’s longest serving trusted advisor to the Contact Centre industry, SVL has grown to become a leading provider of unified cloud communications and telephony…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 16 | 36 contacts → | ||||
Indirect evidence “We specialise in providing unified communication, technology and datacentre services to businesses operating within the private and public sectors throughout the UK and across the…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 17 | 32 contacts → | ||||
Indirect evidence “We are a leading worldwide provider of cloud-based and customer hosted managed visual communication and collaboration services.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 18 | 26 contacts → | ||||
Indirect evidence “Welcome to Radius Connect Solutions.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 19 | 24 contacts → | ||||
Indirect evidence “Mainstream Digital – Communications Solutions for Business Mainstream Digital is a Business Communications solutions provider with over 20 years of telecommunications experience.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 20 | 22 contacts → | ||||
Indirect evidence “Marlin Communications is a UK-based, single-source provider of business communications technology solutions that helps organisations improve customer experiences and optimise how…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 21 | 22 contacts → | ||||
Indirect evidence “Voip Unlimited has been delivering premium telecoms, cloud, and connectivity solutions since 2006, working hand-in-hand with IT and telecoms partners across the UK.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 22 | 19 contacts → | ||||
Indirect evidence “Since 2006, Birmingham Telecom has been helping businesses across the UK with reliable business telecoms, Managed IT Support, Cyber Security and Connectivity Solutions.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 23 | 18 contacts → | ||||
Indirect evidence “MeetingZone was set up in 2002 and has operations in the UK, Germany, USA, Nordics and Asia Pacific.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 24 | 15 contacts → | ||||
Indirect evidence “Communications Reimagined.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 25 | 15 contacts → | ||||
Indirect evidence “ElemenTel are a leading provider of next generation voice over internet (VoIP) telephony solutions to businesses of all types and sizes.” Source: RevenueBase Database · checked Sep 22, 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: ucaas providers. 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 ucaas providers.
- Partial evidence
- Its own public description names part of ucaas providers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name ucaas providers. 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 258 ucaas providers based in the United Kingdom
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Ucaas providers based in the United Kingdom at a glance
As of Sep 22, 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 258 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 ucaas providers, 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 “ucaas providers”. 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 ucaas providers), 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 ucaas providers, 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, 1,472 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 22, 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.
Ucaas providers by metro
- Ucaas providers in London62
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 ucaas providers, 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 ucaas providers are there based in the United Kingdom?
RevenueBase identified 258 ucaas providers 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?
Onecom, headquartered in Whiteley, tops this list with the largest team on record.
Which city has the most ucaas providers?
London leads with 62 headquartered companies, followed by Manchester (6) and Birmingham (5).
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 1,472 verified decision-maker contacts tracked across these 258 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 22, 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.