| Adelphi Masterfil Limited | Haywards Heath | 2007 |
| Adelphi Orthodontics Limited | Edgware | 1998 |
| Adelphi Technologies Ltd | London | 2009 |
| Adelphi Universal Limited | London | 2019 |
| Adem Roast & Export Ltd | London | 2025 |
| Ademex Technologies Ltd | London | 2024 |
| Aden Electronics Limited | Ashford | 1989 |
| Aden Fashion Ltd | London | 2021 |
| Aden Maintenance Ltd | Solihull | 2024 |
| Aden Pro-Form Holdings Limited | Poole | 2021 |
| Aden Pro-Form Limited | Poole | 1996 |
| Adenai Ltd | Enfield | 2024 |
| Adeniyi Design Ltd | Croydon | 2008 |
| Adennill CYF. | Corwen | 2019 |
| Adenville Ltd | Staines-Upon-Thames | 1996 |
| Adenzo Sports Ltd | Kington | 2025 |
| Adeo Associates Ltd | Steyning | 2010 |
| Adeor Limited | London | 2024 |
| Adeorl Limited | London | 2025 |
| Adeplast&Paint Ltd | Farnborough | 2025 |
| Adept (BPT) Limited | Nottingham | 2004 |
| Adept Automation Ltd | St. Albans | 2021 |
| Adept Bespoke Project Solutions Ltd | Melton Mowbray | 2025 |
| Adept Computer Services Limited | Leeds | 2004 |
| Adept Conveyor Belting Midlands Ltd | Nottingham | 2017 |
| Adept Electrical Solutions Ltd | Stockton-On-Tees | 2016 |
| Adept Electronic Services Limited | Gillingham | 2016 |
| Adept Fabrications (Hull) Limited | Kingston Upon Hull | 2006 |
| Adept Fabrications Limited | Shefford | 2004 |
| Adept Graphics Limited | Witney | 2015 |
| Adept GRP Ltd | Ammanford | 2004 |
| Adept Manufacturing Limited | Halesworth | 2024 |
| Adept Precision Limited | Gloucester | 2016 |
| Adept Precision Sheetmetal Limited | Whitchurch | 1986 |
| Adept PS Ltd | Bingley | 2025 |
| Adept Solutions (GB) Limited | Wakefield | 2003 |
| Adept Tooling Limited | Bangor | 2003 |
| Adept Workplace Solutions Limited | Loughborough | 1996 |
| Adept Yorkshire Ltd | Huddersfield | 2017 |
| Adepto Property Group IBD (Luton) Limited | Croydon | 2017 |
| Ades Limited | London | 2004 |
| Ades-Devine Heritage Limited | Wolverhampton | 2023 |
| Adessh Global Refrigeration and Air-Conditioning Ltd | Newcastle Blyth | 2025 |
| Adesso Technology UK Ltd | Wilden | 2021 |
| Adewick Ltd | Sheffield | 2025 |
| Adex Terra Limited | Falkirk | 2025 |
| Adexsteel Ltd | London | 2022 |
| Adey Commercial Limited | Haresfield | 2017 |
| Adey Steel Limited | Loughborough | 1989 |
| Adey Steelshop Ltd. | Loughborough | 1993 |
| Adeysapphire Design Limited | London | 2014 |
| ADF Milking Limited | London | 2009 |
| ADF Scale Company Limited | Hednesford | 1987 |
| Adfab Engineering Limited | Mexborough | 1996 |
| Adfix Sign Holding Ltd | Dundee | 2018 |
| Adflare Digital Limited | Torquay | 2025 |
| ADG DL Limited | West Byfleet | 2025 |
| ADG Fashion Ltd | Bolton | 2019 |
| ADG Foods Ltd | | 2006 |
| ADG Manufacturing Limited | Edinburgh | 2025 |
| ADG Metalworkers Ltd. | Lothians | 2004 |
| Adgan Electrics Ltd | Cheadle | 2024 |
| Adgey Awnings and Shutters Ltd | Lisburn | 2015 |
| Adglow (Installations) Limited | Tewkesbury | 2010 |
| Adgroup Ventures Limited | North Yorkshire | 2006 |
| ADH Composites Ltd | New Milton | 2020 |
| ADH Mechanical Services Limited | Milnrow | 2012 |
| ADH Shipwright Limited | Poole | 2001 |
| Adhd Advantage Limited | Dagenham | 2023 |
| Adhdaf Ltd | Walton On Thames | 2026 |
| Adhesive Backed Materials Ltd | Tredegar | 2003 |
| Adhesive Coatings Limited | Rochdale | 1986 |
| Adhesive Design Limited | Clevedon | 2010 |
| Adhesive Developments Limited | Bury | 1967 |
| Adhesive Specialities Limited | Newbury | 1969 |
| Adhesive Supply Company Ltd | Sutton Coldfield | 2016 |
| Adhesive Technologies UK Limited | Liphook | 2024 |
| Adhesives & Sealants Limited | Altrincham | 2002 |
| Adhesives Direct UK Limited | Walsall | 1994 |
| Adhiban Cosmetics Limited | Hull | 2024 |
| Adhoc On-Site Services Limited | Melton Mowbray | 2024 |
| Adhv Ltd | Whitstable | 2014 |
| Adhyams Ltd | Dartford | 2026 |
| ADI AMA Ltd | Cambridge | 2025 |
| ADI Bespoke Woodwork Ltd | Ramsgate | 2024 |
| ADI Carpentry Ltd | High Wycombe | 2022 |
| ADI Hangu 1976 Ltd | Cambridge | 2024 |
| ADI Motorsport Ltd | Cambridge | 2026 |
| ADI Scaffold Products Ltd | Brierley Hill | 2012 |
| ADI Treatments (Holdings) Limited | West Midlands | 1999 |
| ADI Treatments Limited | Doranda, West Bromwich | 1999 |
| ADI Veli Limited | Thornton Heath | 2024 |
| Adi's Coffee Beans Limited | Milton Keynes | 2025 |
| Adiabatic Service Limited | Derby | 2021 |
| ADIADRIAN65 Ltd | London | 2025 |
| Adianta Ltd | London | 2013 |
| Adient Seating UK Ltd | London | 1947 |
| Adiera Limited | Birmingham | 2007 |
| Adifive Ltd | Plymouth | 2024 |
| Adikctd Ltd | Milton Keynes | 2022 |