| ALL Well Brown Limited | Wholesale & retail | 2024 |
| ALL Work & Social (ABC) Limited | Real estate | 2019 |
| ALL Work and Social Bonded Limited | Real estate | 2017 |
| ALL Work and Social G&S Limited | Professional & scientific | 2017 |
| ALL Work and Social Holdco Limited | Financial services | 2020 |
| ALL Work and Social Leeds Dock Limited | Real estate | 2020 |
| ALL Work and Social Limited | Professional & scientific | 2024 |
| ALL Work and Social Operations Limited | Real estate | 2023 |
| ALL Year Trading Ltd. | Wholesale & retail | 2000 |
| ALL Your Company Ever Needs Limited | Wholesale & retail | 2002 |
| All-Tec Repairs Ltd | Extraterritorial | 2012 |
| All-Time High (ATH) Entertainment Ltd | Hospitality | 2026 |
| ALL4AUTOS Ltd | Wholesale & retail | 2023 |
| ALL4INCLUSION CIC | Education | 2022 |
| Alla Properties Ltd | Real estate | 2024 |
| Alladeen Ltd | Wholesale & retail | 2021 |
| Allan & Newton Holdings Limited | Professional & scientific | 2021 |
| Allan Rosen Limited | Information & communication | 2000 |
| Allan Shearer Subsea Projects Ltd | Other services | 2014 |
| Allandale Solutions Ltd | Real estate | 2021 |
| Allanson Consulting Limited | Information & communication | 2015 |
| Allblue WL Ltd | Wholesale & retail | 2023 |
| Allbokos Ltd | Agriculture & fishing | 2022 |
| Allbreeds Grooming (UK) Ltd. | Other services | 2024 |
| Allbricks Original Ltd | Extraterritorial | 2011 |
| Allbro's Pharmacy Ltd | Wholesale & retail | 2010 |
| Allbro's Properties Limited | Real estate | 2019 |
| Allcall Group Ltd | Households | 2020 |
| Allcall Services Ltd | Households | 2022 |
| Allchin Properties Ltd | Real estate | 2025 |
| Alldatacompany Ltd | Professional & scientific | 2022 |
| Alldeon Ltd | Information & communication | 2026 |
| Alldev Ltd | Information & communication | 2021 |
| Alldoq Limited | Information & communication | 2022 |
| Allee Investments Limited | Real estate | 2023 |
| Allegiance Recruitment Group Limited | Administrative & support | 2025 |
| Allegiance Technology Limited | Administrative & support | 2021 |
| Allegra Developments Ltd | Households | 2026 |
| Allegra Investments Limited | Professional & scientific | 2019 |
| Allen a Harvey Ltd | Professional & scientific | 2022 |
| Allen Consultancy and Engineering Limited | Administrative & support | 2013 |
| Allen Resources Limited | Information & communication | 2019 |
| Allendale Court Management Company Limited | Real estate | 1986 |
| Allendale Developments Limited | Real estate | 2004 |
| Allendale Rest Home Ltd | Health & social care | 2001 |
| Allens Bakery & Confectionery Ltd | Manufacturing | 2011 |
| Allerbeste International UK Ltd | Professional & scientific | 2023 |
| Allergydoctor UK Limited | Professional & scientific | 2014 |
| Allery Holdings Limited | Professional & scientific | 2022 |
| Alleviate Consulting Limited | Professional & scientific | 2013 |
| Allforalbion Ltd | Wholesale & retail | 2026 |
| Allgood Construction (NW) Ltd | Construction | 2023 |
| Allgreen Garden Services Ltd | Administrative & support | 2026 |
| Allgreen Tree Services Ltd | Agriculture & fishing | 2026 |
| Allguard Alarms Limited | Construction | 1989 |
| Alliance & Cooper Solicitors Ltd | Professional & scientific | 2018 |
| Alliance and Brave Consultancy Ltd | Administrative & support | 2020 |
| Alliance Chemicals Holding Company Limited | Financial services | 2013 |
| Alliance Design UK Ltd | Construction | 2005 |
| Alliance Family Foundation Limited | Health & social care | 1968 |
| Alliance for General Trading Limited | Extraterritorial | 2026 |
| Alliance Inventory & Property Maintenance Ltd | Construction | 2026 |
| Alliance Legal Group Ltd | Professional & scientific | 2022 |
| Alliance Petroleum Ltd | Wholesale & retail | 2023 |
| Alliance Property Asset Management Limited | Real estate | 2014 |
| Alliance Property Ventures Ltd | Real estate | 2026 |
| Alliance Real Estate LLP | | 2014 |
| Alliance Retail & Distribution Limited | Wholesale & retail | 2016 |
| Alliance Taxis Limited | Transport & logistics | 2004 |
| Alliance Trade & Distribution Limited | Transport & logistics | 2016 |
| Alliance Travel Group Ltd | Financial services | 2025 |
| Alliance UBS Limited | Construction | 2022 |
| Allibobo Ltd | Wholesale & retail | 2022 |
| Allicom Consultancy Limited | Information & communication | 2022 |
| Allied & Clinical Recruitments Limited | Administrative & support | 2009 |
| Allied & Equity Ltd | Real estate | 2006 |
| Allied Business Services Rochdale Limited | Financial services | 2022 |
| Allied Capital Financials Limited | Professional & scientific | 2017 |
| Allied Diagnostic Services Limited | Health & social care | 2022 |
| Allied Filter Systems Group Limited | Financial services | 2024 |
| Allied Filter Systems Holdings Limited | Real estate | 2016 |
| Allied Filter Systems Limited | Manufacturing | 1995 |
| Allied Health Training Limited | Education | 2022 |
| Allied Jubille Limited | Real estate | 2025 |
| Allied Knitwear Limited | Manufacturing | 2004 |
| Allied London (Pavilion) Limited | Real estate | 2016 |
| Allied London Campfield Developments Limited | Construction | 2018 |
| Allied London Canal Limited | Real estate | 2018 |
| Allied London Castlefield Holding Company Limited | Real estate | 2016 |
| Allied London Castlefield House Holdco Limited | Real estate | 2016 |
| Allied London Development Holdings Limited | Real estate | 2018 |
| Allied London Development Management Five Limited | Real estate | 2024 |
| Allied London Development Management Four Limited | Real estate | 2022 |
| Allied London Development Management Holdco Limited | Real estate | 2020 |
| Allied London Development Management Limited | Real estate | 2011 |
| Allied London Development Management SIX Limited | Real estate | 2024 |
| Allied London Development Management Three Limited | Real estate | 2017 |
| Allied London Developments Five Limited | Construction | 2022 |
| Allied London Developments One Limited | Construction | 2022 |
| Allied London Developments Three Limited | Construction | 2022 |