| Adelhaven Limited | London | 1987 |
| Adeline Glass Creations Ltd | Dunmow | 2017 |
| Adelle Moss Ltd | Bedford | 2016 |
| Adelong Expeditions - Highlands and Islands Limited | Brixham | 2015 |
| Adelong Outdoor Education Limited | Brixham | 2014 |
| Adelphi Events Management Ltd | High Wycombe | 2012 |
| Adelphi Music Factory Limited | Chesterfield | 2018 |
| Adelphi Theatre Holdings Limited | London | 1988 |
| Adelphoi Music Limited | | 2002 |
| Aden Brands Limited | London | 2011 |
| Aden Fitness & Wellbeing for Women Ltd | Halifax | 2024 |
| Adenaike Ltd | Liverpool | 2025 |
| Adeptclub Ltd | Huddersfield | 2022 |
| Adeshokan Ltd | Worthing | 2021 |
| Adesso Events Ltd | Banchory | 2016 |
| Adesso Ltd | Torquay | 2025 |
| Adeyemi Fitness Limited | Barnet | 2021 |
| ADG Motorsport Limited | London | 2026 |
| ADG Music Services Ltd | Newbury | 2025 |
| ADG Sports Therapy Coaching Services Limited | Bedford | 2026 |
| Adgespeed Limited | Manchester | 2006 |
| Adgs Hexagon Jvco Limited | London | 2023 |
| Adgs Holdco Limited | London | 2023 |
| ADH3 Theatre Ltd | Dundee | 2025 |
| Adhoc Entertainment Ltd | Romford | 2005 |
| Adhoc Productions Limited | London | 1974 |
| Adhub Ltd | Bamford | 2019 |
| Adhyayanam Ltd | Milton Keynes | 2023 |
| ADI Competitions Ltd | Wirral | 2026 |
| ADI Racing Ltd | Harrow | 2022 |
| Adikkal Nayagarkal Ltd | Rothwell | 2025 |
| Adil Rashid Cricket Academy Ltd | Bradford | 2012 |
| Adinkra Jackpot Ltd | Cardiff | 2025 |
| Adinkra Kete Group UK Ltd | London | 2022 |
| Adinkra Kingdom Ltd | London | 2024 |
| Adinkra Music Ltd | Hove | 2018 |
| Adinkrahene Ltd | London | 2024 |
| Adips Limited | Sunderland | 2003 |
| Adira Events and Courses Ltd | Attleborough | 2021 |
| Adira Performance Ltd | Attleborough | 2018 |
| Adisto Ltd | London | 2020 |
| Aditi Sport Ltd | Banbury | 2019 |
| Adity Dance CIC | Woodford Green | 2023 |
| Adiva Forever Ltd | Dagenham | 2011 |
| Adiyogi HC Ltd | Purley | 2026 |
| ADJ Events Ltd | Loughborough | 2016 |
| ADJ Management Ltd | Selby | 2026 |
| Adjuvant Ltd | Port Glasgow | 2009 |
| Adjuvo Studios Limited | London | 2016 |
| ADK Creative Ltd | Southwell | 2011 |
| ADK Productions Ltd | Essex | 2016 |
| Adkin Freeman Vitality Ltd | Greenford | 2024 |
| ADL Braklin Sport and Entertainment Limited | Birmingham | 2023 |
| Adlards a Star Fitness Ltd | Hull | 2023 |
| Adlc Limited | Coventry | 2018 |
| Adlib Audio Limited | Prescot | 1998 |
| Adlington Petting Farm Ltd | Stockport | 2016 |
| Adly Fitness Limited | Houghton Le Spring | 2025 |
| ADM Diving & Technical Services Limited | Coalville | 2005 |
| Adma Productions Limited | Bloxham | 2024 |
| Admiral Costumes Ltd | Knebworth | 2025 |
| Admire Fitness Ltd | Bishop Auckland | 2024 |
| Adnan Cricket Academy Limited | London | 2020 |
| ADO15 Ltd | London | 2015 |
| Adobo Limited | London | 2012 |
| Adolescent Productions Ltd | London | 2020 |
| Adom Balloons Limited | Purfleet-On-Thames | 2016 |
| Adonis Cabaret Limited | Brighton | 2002 |
| Adonis Fitness Limited | Limavady | 2015 |
| Adonis Records Limited | Bristol | 2019 |
| Adopt a Potter Limited | London | 2017 |
| Adorable Dorks Events Limited | London | 2025 |
| Adore Arts Ltd | Birmingham | 2020 |
| Adore-A-Ball Ltd | Congleton | 2025 |
| Adorn Events Co Ltd | Leicester | 2019 |
| Adorn Global Limited | Borough | 2012 |
| Adorn Your Walls Ltd | London | 2021 |
| Adotd Consulting Ltd | Newark | 2024 |
| Adoy Ltd | Orpington | 2025 |
| ADP Works Ltd | London | 2018 |
| ADP501 Ltd | London | 2019 |
| Adpt Ltd | Birmingham | 2026 |
| ADR Thoroughbreds Ltd | Batley | 2026 |
| Adreango+ Limited | London | 2025 |
| Adrenalin (North Yorkshire) Limited | Richmond | 2002 |
| Adrenalin Addicts Ltd | Dolgellau | 2023 |
| Adrenalin Jungle Limited | Newark | 2006 |
| Adrenalin Leisure Limited | Honiton | 2016 |
| Adrenalin Promotions Ltd | Birmingham | 2005 |
| Adrenalin Quarry Limited | Liskeard | 2009 |
| Adrenalin Rush (Europe) Limited | London | 2012 |
| Adrenalin Shock Limited | Richmond | 2016 |
| Adrenaline Alley | Corby | 2006 |
| Adrenaline and Endorphin Productions Ltd | Chatham | 2016 |
| Adrenaline Escape Atherton Ltd | Manchester | 2015 |
| Adrenaline Escape Ltd | Blackburn | 2024 |
| Adrenaline Escape Wigan Ltd | Blackburn | 2024 |
| Adrenaline International Limited | Carlisle | 2015 |
| Adrenaline Leisure Limited | Coventry | 2002 |
| Adrenaline Martial Arts - JT Ltd | Haverhill | 2025 |