| A-Rated Shine Ltd | Bradford | 2025 |
| A-Ray-Tec Services (Management) Limited | Yelverton | 1986 |
| A-Rec Education Limited | Bedford | 2021 |
| A-Rec Solutions Limited | Bedford | 2017 |
| A-Sec Installations Ltd | Sheffield | 2025 |
| A-Secure Electronic Security Ltd | Derby | 2025 |
| A-Sonic Logistics (UK) Limited | Bromley | 2017 |
| A-Spec Homes Ltd | Hove | 2012 |
| A-Star Care Solutions Limited | Sale | 2022 |
| A-Star Castles Ltd | Ipswich | 2025 |
| A-Star Domestic and Commercial Services Ltd | Greater Manchester | 2020 |
| A-Star Gardening & Landscaping Ltd | Northampton | 2024 |
| A-Star Pupils Tuition Ltd | London | 2021 |
| A-Star Security Solutions Ltd | Leamington Spa | 2025 |
| A-Star Will & Estates Planning Limited | Hayes | 2025 |
| A-Sync Recruitment Ltd | London | 2025 |
| A-Talents Limited | London | 2020 |
| A-Talks Ltd | Deeside | 2025 |
| A-Talnt Company Ltd | London | 2025 |
| A-Team Care Ltd | Hove | 2014 |
| A-Team Carpet Clean Ltd | Redditch | 2025 |
| A-Team Cleaning Services Limited | London | 2020 |
| A-Team Health Recruitment Limited | Birmingham | 2004 |
| A-Team Staffing Ltd | Worcester | 2024 |
| A-Team Tree Surgery & Garden Services Ltd | Edinburgh | 2024 |
| A-Tech Recruitment Ltd | London | 2020 |
| A-Tint Edinburgh Ltd | Edinburgh | 2023 |
| A-Trax Group Ltd | Reading | 2015 |
| A-Type VIP Ltd | Bexley | 2026 |
| A-United Recruitment Limited | London | 2022 |
| A-Va (Virtual Assistant) Ltd | Rochdale | 2023 |
| A-Vert Fire Risk & Management Services Ltd | Lancs | 2006 |
| A-Viaggi Limited | London | 1985 |
| A-Yalife Group Limited | Nottingham | 2024 |
| A-Z Animal Care Limited | Tenterden | 2006 |
| A-Z Apprenticeship Consultancy Ltd | Leicester | 2026 |
| A-Z Assist Ltd | Manchester | 2024 |
| A-Z Auto Repair Ltd | London | 2023 |
| A-Z Brand Management Limited | London | 2024 |
| A-Z Cleaning Service Ltd | Southampton | 2024 |
| A-Z Complete Care Ltd | Barking | 2023 |
| A-Z Consultants Ltd | Melksham | 2008 |
| A-Z Ecoshine Ltd | Gainsborough | 2025 |
| A-Z Events Management Limited | London | 2013 |
| A-Z Landscaping& Construction Ltd | Glasgow | 2025 |
| A-Z Management Consultancy Ltd | Bolton | 2023 |
| A-Z Master Builders Ltd | Wembley | 2022 |
| A-Z Quest Ltd | Edinburgh | 2024 |
| A-Z Rentals Ltd | London | 2024 |
| A-Z Secure Solutions Ltd Ltd | Bradford | 2024 |
| A-Z Security Services Ltd | Luton | 2019 |
| A-Z Security-Event Limited | London | 2014 |
| A-Z Support Services Limited | Leicester | 2023 |
| A-Z Wash Ltd | London | 2020 |
| A-Z Yachting Ltd | Poole | 2019 |
| A-Zcleaners Limited | Manchester | 2013 |
| A-Zed Cars Ltd | London | 2026 |
| A-Zvaletingservices Ltd | Ashford | 2025 |
| A. & a. Bell Marquee Hire Limited | Plymouth | 1998 |
| A. & H. Nominees Limited | London | 1967 |
| A. a. Chemical Cleaning Company Limited | Eccles | 1996 |
| A. a. Roestenburg & Associates Limited | Hitchin | 2001 |
| A. a. Security Ltd | Ilford | 2021 |
| A. Ardron Limited | Barnsley | 2003 |
| A. B. S. Plant Hire Limited | Faringdon | 2005 |
| A. Bhagat Limited | Leicester | 2014 |
| A. Bird Tree Surgery Ltd | Herne Bay | 2015 |
| A. Bothwell Plant Hire Ltd. | Cambridge | 2004 |
| A. Bradwell (UK) Ltd | Ashton-U-Lyne | 2016 |
| A. C. Cleaning Services (Wolverhampton) Limited | Willenhall | 2002 |
| A. C. Colquhoun Ltd | London | 2017 |
| A. C. Gardens ( Sussex ) Ltd. | Arundel | 2018 |
| A. Cowley & Sons Limited | Worksop | 1995 |
| A. Day to Remember Chester Ltd. | Chester | 2009 |
| A. Dennison & Co. Limited | Surrey | 2002 |
| A. Design Company London Limited | Guildford | 2007 |
| A. Doherty Plant Hire Limited | Londonderry | 2023 |
| A. Edwards Limited | Marlow | 1988 |
| A. F. Cooper 1962 Ltd | Bognor Regis | 2025 |
| A. F. M. Design Ltd | Manchester | 2005 |
| A. Fabrications Ltd | Manchester | 2019 |
| A. Fielding Ltd | St. Ives | 2008 |
| A. Frizell Limited | Carlisle | 2003 |
| A. Garner Rail Pipe Solutions Ltd | Rock | 2007 |
| A. J. Bone & Sons Limited | Southend-On-Sea | 2017 |
| A. J. Down to Earth Limited | Waltham Cross | 2009 |
| A. J. Loach Plant Hire Limited | West Midlands | 1992 |
| A. J. Nicholl Properties Limited | Stafford | 2006 |
| A. J. Tyzack & Co Limited | Stockport | 2000 |
| A. Jeffries Recruitment Limited | March | 2013 |
| A. Jensen Snekkerservice OG Vedlikehold Ltd | Stockport | 2010 |
| A. Johnston I.T. Services Ltd | Markfield | 2005 |
| A. K. T. International Limited | Eastbourne | 2009 |
| A. L. E. Consulting Limited | Worthing | 2004 |
| A. L. M. Services Limited | High Wycombe | 2003 |
| A. L. Shipping Ltd | London | 1991 |
| A. LEE Electrical Limited | Warrington | 2016 |
| A. M. Contract Cleaning Limited | Widnes | 2013 |
| A. M. Expert Cleaning Limited | Coventry | 2025 |
| A. M. Kenilworth Limited | London | 2009 |