| Alchemie Materials Limited | Bury St. Edmunds | 2002 |
| Alchemist Candles Ltd | Thornton Heath | 2020 |
| Alchemist Fabrications Limited | Nottingham | 2025 |
| Alchemist Perfumery Ltd | London | 2024 |
| Alchemist Technologies Ltd | Leeds | 2022 |
| Alchemy Architectural Aluminium Systems Limited | Halesowen | 2005 |
| Alchemy Brands Ltd | Norwich | 2024 |
| Alchemy Collectives Limited | Warrington | 2025 |
| Alchemy Corp Limited | Ramsgate | 2022 |
| Alchemy Cosmetics & Personal Care Ltd | London | 2025 |
| Alchemy Design & Works Limited | Northallerton | 1992 |
| Alchemy Diamonds Ltd | Belfast | 2022 |
| Alchemy Distil Ltd | Belfast | 2018 |
| Alchemy Distilling Ltd | Aldershot | 2019 |
| Alchemy Furniture Limited | Reading | 2009 |
| Alchemy Home Furnishings Ltd | Ipswich | 2023 |
| Alchemy Interactive Limited | Beaconsfield | 1998 |
| Alchemy Oilfield Services Limited | Aberdeen | 2005 |
| Alchemy Oils Ltd | Derby | 2013 |
| Alchemy Plus Ltd | Bridgend | 2018 |
| Alchemy Products Limited | Brampton | 2007 |
| Alchemy Technical Consulting Limited | St Asaph Business Park | 2001 |
| Alchemy Technologies Limited | Swansea | 2002 |
| Alchemy Wellbeing Ltd | Cheltenham | 2014 |
| Alchetex Ltd | London | 2021 |
| Alchris Audio Limited | Wakefield | 2021 |
| Alchymis Ltd | Brighton | 2025 |
| Alcifan Realisations Limited | Birstall | 1964 |
| Alcina Engineering Ltd | Warwick | 2015 |
| Alcina Ltd | London | 2012 |
| Alcme Limited | Walsall | 2013 |
| Alco Engineering (Manufacturing) Ltd | Torrington | 2014 |
| Alco Engineering Company (Sheet Metal) Limited | N Devon | 1961 |
| Alco Glass Systems Limited | Amersham | 1998 |
| Alco Hi-Tek Limited | Brighouse | 2020 |
| Alco Knitting Machine Services Limited | Kirkby In Ashfield | 2002 |
| Alco Manufacturing Limited | Ellesmere Port | 2003 |
| Alco Shield Limited | Stalybridge | 2011 |
| Alco Valves Group Limited | Brighouse | 1998 |
| Alco Valves Limited | Brighouse | 2020 |
| Alco-Tech UK Ltd | Surrey | 2025 |
| Alcoholery Ltd | Bath | 2023 |
| Alcohols Limited | Rugby | 1955 |
| Alcolyser Limited | Cowbridge | 1980 |
| Alcon Advanced Technologies Limited | London | 2019 |
| Alcon Components Limited | London | 1991 |
| Alcon Laboratories (U.K.) Limited | Camberley | 1969 |
| Alconkoc UK Ltd | London | 2026 |
| Alconn Kitchens Limited | Belfast | 2004 |
| Alcotox Ltd | London | 2012 |
| Alcove Cabinet Company Limited | Whitley Bay | 2021 |
| Alcove Carpentry Limited | London | 2010 |
| Alcove Designs Ltd | London | 2007 |
| Alcraft Motor Company Ltd | Lincoln | 2014 |
| Alcurt Textiles Limited | Manchester | 2013 |
| Alcyone Jewellery Ltd | Dunbar | 2023 |
| ALD Carpentry Ltd | Bristol | 2024 |
| ALD Race Engines & Heads Ltd | Leeds | 2023 |
| ALD Solutions Ltd | Worthing | 2025 |
| Alda Plastics Limited | Eastleigh | 2007 |
| Aldahar Ltd | Glasgow | 2025 |
| Aldam Tech Ltd | Newry | 2024 |
| Aldar I Limited | Manchester | 2025 |
| Aldass Ltd | Syston | 2025 |
| Aldbake Limited | Rochdale | 2020 |
| Aldborough Energy Supplies Limited | York | 2014 |
| Aldburgh Design Limited | London | 2023 |
| Aldbury Products Ltd. | Newmarket | 2006 |
| Aldcroft Adhesives Limited | Bolton | 1983 |
| Alde Engineering Limited | Saxmundham | 2011 |
| Alde International (UK) Limited | Wellingborough | 2008 |
| Aldeburgh Boatyard Co.Limited | Aldeburgh | 1966 |
| Aldec (Scotland) Limited | Uddingston | 1960 |
| Alden Machinery Ltd | Waltham Cross | 2024 |
| Alden Repairs & Maintenance Ltd | London | 2021 |
| Alden Sheetmetal Fabrications Limited | Southampton | 1984 |
| Alder Tree Limited | Suffolk | 2007 |
| Alder Windows & Doors Limited | Minehead | 1991 |
| Aldercote Limited | Sheffield | 1999 |
| Aldercroft Ltd | Ipswich | 2022 |
| Alderelm Limited | Manchester | 1982 |
| Alderley Holdings Limited | London | 2018 |
| Alderley Mowers & Machinery Ltd | Wilmslow | 2004 |
| Alderley Process Technologies Limited | Wotton-Under-Edge | 1992 |
| Alderley Systems Ltd | 1 Oxford Street | 1985 |
| Alderley Ventures Limited | London | 2018 |
| Alderman Tooling Limited | Plympton | 1988 |
| Alderney Plating Limited | Poole | 1986 |
| Alders Paper Converters Limited | Tamworth | 2013 |
| Alders Scientific Corporation Ltd | West Midlands, England, | 2022 |
| Aldershaw Handmade Tiles Limited | Sedlescombe Battle | 1995 |
| Alderson & Co Limited | Walton-On-Thames | 2012 |
| Alderson Ferry Ltd | Heckmondwike | 2026 |
| Alderson Glass Engineering Ltd | Morecambe | 2025 |
| Aldersons(Engineering)Limited | Merseyside | 1962 |
| Alderwood Electrical Limited | Banbury | 1999 |
| Alderwood Fitted Furniture Limited | Hull | 2004 |
| Alderwood Forge Ltd | Cirencester | 2026 |
| Aldgate Press Limited | London | 2005 |
| Aldine Print Limited | Malvern | 2001 |