| A Legendary Enterprise Limited | Leeds | 2022 |
| A Lethem Ltd | London | 2023 |
| A Liaqat Ltd | Heywood | 2023 |
| A Life Companion Ltd | Warwick | 2026 |
| A Life in Tandem Productions Ltd | Bristol | 2023 |
| A Life Less Ordinary SOC Limited | Billingshurst | 2016 |
| A Life More Extraordinary Ltd | London | 2025 |
| A Lifetime on the Hips Ltd | Saffron Walden | 2024 |
| A Light in the Dark Films Limited | London | 2011 |
| A Likkle Louder Limited | London | 2026 |
| A Lincoln Limited | Chatham | 2024 |
| A Little Aesthetic Ltd | Sheffield | 2017 |
| A Little Big Limited | Warwick | 2012 |
| A Little Bird Ltd | Blisworth | 2026 |
| A Little BIT About Limited | Horley | 2013 |
| A Little BIT of Slope Limited | York | 2022 |
| A Little Book Problem Limited | Doncaster | 2023 |
| A Little Company About Lemons Limited | Port Talbot | 2014 |
| A Little Enterprises Ltd | Ealing | 2025 |
| A Little Tonic Limited | London | 2025 |
| A Little Wayward Ltd | Dundee | 2025 |
| A Load of BS Ltd | Northampton | 2024 |
| A Long Tale and Two Branches Ltd | London | 2021 |
| A Long Winter Films Ltd | London | 2024 |
| A Lozza Lozza Laughs Ltd | Warwick | 2021 |
| A Lutley Consultancy Limited | Woking | 2007 |
| A Lynch Consulting Limited | London | 2018 |
| A Lynch Ltd | London | 2019 |
| A M B S Media Ltd | Bromsgrove | 2025 |
| A M Consultants (Hereford) Ltd | Stourbridge | 2014 |
| A M Crace Limited | London | 2012 |
| A M D Computer Solutions Limited | Kendal | 2000 |
| A M Daley Ltd | Bournemouth | 2013 |
| A M E Electronics Limited | Glasgow | 2008 |
| A M J Technology Limited | London | 2025 |
| A M K Consulting Engineers Limited | Belfast | 2013 |
| A M Media Consultants Limited | Nottingham | 2014 |
| A M Nettech Limited | Wimborne | 2024 |
| A M Network Services Limited | Bristol | 2016 |
| A M Roper Consulting Limited | Milton Keynes | 2019 |
| A M Software Solutions Ltd | Manchester | 2025 |
| A M Szwagrzak Limited | London | 2014 |
| A M V Works Ltd | London | 2026 |
| A M Walker Film & TV Ltd | London Colney | 2025 |
| A Majid Ltd | Maidenhead | 2015 |
| A Makkan Ltd | Blackburn | 2022 |
| A Man's Story Films Limited | Nottingham | 2008 |
| A MAP of US Ltd | London | 2025 |
| A Marlow's Production Ltd | Colindale | 2021 |
| A Matter of Code Ltd | Bury St. Edmunds | 2024 |
| A Matter of Words Ltd | London | 2022 |
| A Matthews Ltd | Whitehills Business Park | 2019 |
| A Maze Inc. Ltd | Witney | 2013 |
| A Media Solutions Limited | London | 2012 |
| A Memorable Ennui Limited | Romford | 2026 |
| A Memoria D’Uomo Limited | London | 2025 |
| A Mighty Stranger Limited | London | 2022 |
| A Million Days Production Ltd | London | 2021 |
| A Million Years Ltd | London | 2025 |
| A Miracle Production Limited | London | 2025 |
| A Mistry Productions Limited | Manchester | 2024 |
| A Modern Way Limited | Sheffield | 2014 |
| A Monroe Ltd | Ruislip, | 2026 |
| A Morgan Telecoms Limited | Barnsley | 2018 |
| A Most Wanted MAN Limited | London | 2012 |
| A Mother Place Limited | London | 2016 |
| A Music Company Limited | Borough | 1996 |
| A N B Business Services Limited | Chigwell | 2010 |
| A N Consulting Services Limited | Telford | 2024 |
| A N Global Services Ltd | Harrow | 2019 |
| A N P Research Ltd | Bolton | 2024 |
| A N Q Music Ltd | Bingley | 2023 |
| A N Software Solutions Ltd | Liverpool | 2022 |
| A Napleton Film Limited | London | 2023 |
| A Nathan Newman Thing Ltd | Ashtead | 2024 |
| A Networks Media Ltd | Winchester | 2024 |
| A New Day Ltd | London | 2016 |
| A New Icon Limited | Hove | 2022 |
| A New Nation Entertainment Limited | Dartford | 2025 |
| A New Road Productions Ltd | Llandovery | 2025 |
| A New Solution Limited | Surrey | 2005 |
| A Nice Drop Limited | Haywards Heath | 2022 |
| A Noodles Production Ltd | London | 2012 |
| A NOS Amours Ltd | London | 2013 |
| A Number 10 Production Limited | London | 2018 |
| A Number Films Limited | London | 2006 |
| A O IT Consultancy Services Limited | Ilford | 2009 |
| A Odedra Limited | Leighton Buzzard | 2019 |
| A OK Productions Limited | Hove | 2023 |
| A One Games UK Limited | London | 2023 |
| A One Star Marketing Limited | Brentford | 2014 |
| A One Transport (Leeds) Limited | Batley | 2001 |
| A P Beswick Publications Ltd | Pickup Street | 2023 |
| A P C Solutions (UK) Limited | Kelvedon | 1998 |
| A P Costumes Limited | London | 2016 |
| A P Logistics Limited | Swansea | 1983 |
| A P Lyon Ltd | Chippenham | 2015 |
| A P Maritime Limited | Lymington | 2014 |
| A P Planning Practice Ltd | London | 2013 |
| A P Records Ltd | Sutton Coldfield | 2015 |