| Albany Park Mortgages Limited | Financial services | 2024 |
| Albany Road Visionplus Limited | Wholesale & retail | 2003 |
| Albino Consulting Ltd | Administrative & support | 2021 |
| Albion Investment Group Ltd | Real estate | 2021 |
| Albion Operations Ltd | Information & communication | 2026 |
| Alcester Specsavers Limited | Wholesale & retail | 2018 |
| ALD Labradoodles UK Limited | Agriculture & fishing | 2020 |
| Aldercape Ltd | Construction | 2025 |
| Alderslade Mechanical Services Ltd | Professional & scientific | 2019 |
| Aldridge Specsavers Limited | Wholesale & retail | 2022 |
| Alecto Recruitment Ltd | Administrative & support | 2009 |
| Aledentix Limited | Health & social care | 2023 |
| Alegria Consulting Services Ltd | Information & communication | 2007 |
| Alesvi Advisors Limited | Professional & scientific | 2024 |
| Alex Mortiboys Works Limited | Professional & scientific | 2024 |
| Alex Pynen Limited | Health & social care | 2023 |
| Alexander Chisholm Construction Limited | Construction | 2024 |
| Alexander Vaughan Limited | Professional & scientific | 2011 |
| Alexandrite Property Ltd | Real estate | 2020 |
| ALFA1 (U.K.) Limited | Administrative & support | 2023 |
| ALFA1 Properties Ltd | Real estate | 2026 |
| Alfred Thomas Consultancy Limited | Information & communication | 2008 |
| Alfreton Specsavers Hearcare Limited | Wholesale & retail | 2024 |
| Alfreton Specsavers Limited | Wholesale & retail | 2007 |
| Alfreton Visionplus Limited | Wholesale & retail | 2007 |
| Aligned HR Services Limited | Administrative & support | 2019 |
| Aligned Support Ltd | Health & social care | 2025 |
| Alignment Holdings Ltd | Financial services | 2025 |
| Alimore Limited | Real estate | 1999 |
| Alisa Roberts Photography Ltd | Professional & scientific | 2017 |
| Alison Lucas Consulting Limited | Professional & scientific | 2014 |
| Alissa Healthcare Holdings Limited | Financial services | 2017 |
| Alissa Healthcare Research Limited | Wholesale & retail | 2006 |
| Alive by Design Limited | Administrative & support | 2012 |
| Aljusi Consultancy Limited | Information & communication | 2010 |
| ALL About Accounting (UK) Limited | Professional & scientific | 2011 |
| ALL About Vending Ltd | Extraterritorial | 2010 |
| ALL Around Heating Products Ltd | Construction | 2011 |
| ALL Cars 1 Limited | Wholesale & retail | 2011 |
| ALL Court Wear Ltd | Wholesale & retail | 2026 |
| ALL Executive Travel Ltd | Transport & logistics | 2020 |
| ALL Inclusive Network Limited | Information & communication | 2020 |
| ALL Inclusive Network Services Limited | Information & communication | 2026 |
| ALL Star Events Limited | Arts & recreation | 2010 |
| ALL the Gear Equestrian Ltd | Wholesale & retail | 2025 |
| ALL Things Doozie Ltd | Wholesale & retail | 2024 |
| ALL Thingz Limited | Wholesale & retail | 2020 |
| ALL Time Grates Limited | Wholesale & retail | 2005 |
| ALL Time Grates Wickham Limited | Wholesale & retail | 2023 |
| ALL Trades (North West) Limited | Construction | 2025 |
| ALL Under One Roof Developments Limited | Construction | 2020 |
| All-Mod-Cons-Scooters Ltd | Wholesale & retail | 2012 |
| Allan Packer Capital Limited | Financial services | 2016 |
| Allard & Saunders Limited | Wholesale & retail | 1947 |
| Allbury Limited | Manufacturing | 2006 |
| Allclad Insulation Services Limited | Construction | 2000 |
| Allen Consulting Services (UK) Ltd | Other services | 2020 |
| Allerton Specsavers Hearcare Limited | Wholesale & retail | 2022 |
| Allerton Specsavers Limited | Wholesale & retail | 2005 |
| Allerton Visionplus Limited | Wholesale & retail | 2005 |
| Allestree Specsavers Limited | Wholesale & retail | 2023 |
| Allez France Group Limited | Administrative & support | 1981 |
| Allez France Holiday Homes Limited | Administrative & support | 1992 |
| Alliance Consultants LLP | | 2009 |
| Allied Developments Ltd | Construction | 2004 |
| Allied Secure Transport Ltd | Transport & logistics | 2023 |
| Allito Developments Ltd | Real estate | 2026 |
| Allkins Consultancy Services Ltd | Professional & scientific | 2024 |
| Alloa Specsavers Limited | Wholesale & retail | 2003 |
| Alloo Optical Services Limited | Health & social care | 2013 |
| Allspeed Signs & Graphics Limited | Manufacturing | 1994 |
| Alluk Covered Ltd | Other services | 2015 |
| Ally Filer Consulting Services Limited | Professional & scientific | 2024 |
| ALM Associates Limited | Information & communication | 2013 |
| Alma Land & Property Limited | Other services | 2022 |
| Alnwick Specsavers Limited | Wholesale & retail | 2016 |
| Alpha Aerials Limited | Information & communication | 2016 |
| Alpha Touch Ltd | Information & communication | 1999 |
| Alpinestars UK Limited | Professional & scientific | 2018 |
| Alpoholics Ltd | Hospitality | 2010 |
| Alrita Compliance Services Ltd | Professional & scientific | 2014 |
| ALS Locksmiths Limited | Administrative & support | 2015 |
| ALS Plastics & Decorating Limited | Construction | 2020 |
| ALS Roofing South Limited | Construction | 2020 |
| Altaedge Ltd | Professional & scientific | 2024 |
| Altarma Engineering Ltd | Professional & scientific | 2023 |
| Altera Recruitment Group Ltd | Administrative & support | 2025 |
| Alternative Windscreens Limited | Wholesale & retail | 2012 |
| Althorp Road Specsavers Hearcare Limited | Wholesale & retail | 2019 |
| Althorp Road Specsavers Limited | Wholesale & retail | 2016 |
| Alti Global Ltd | Other services | 2019 |
| Altitude Roofing South Ltd | Construction | 2024 |
| Alto Construction Ltd | Construction | 2025 |
| Alto Marketing Limited | Professional & scientific | 2002 |
| Alton Compressor Services Ltd | Manufacturing | 2019 |
| Alton Powers Ltd | Information & communication | 2021 |
| Alton Specsavers Limited | Wholesale & retail | 2010 |
| Altrincham Specsavers Limited | Wholesale & retail | 1993 |
| Altrincham Visionplus Limited | Wholesale & retail | 1993 |
| Altwegg Hospitality Ltd | Hospitality | 2023 |