| Acquisto Design & Management Limited | Broxbourne | 2013 |
| ACR Marine Ltd | London | 2024 |
| ACR S.A. Ltd. | Manchester | 2024 |
| ACR Scotland Ltd | Larkhall | 2025 |
| Acre Capital Real Estate Holdings Limited | Tunbridge Wells | 2023 |
| Acre Mills (UK) Limited | Mitcham | 1939 |
| Acre Property Consultants Limited | Tunbridge Wells | 2023 |
| Acre Shoes Ltd. | London | 2020 |
| Acre Sulis Ltd | Biggleswade | 2024 |
| Acreations Ltd | Shefford | 2024 |
| Acredeed Limited | Dagenham | 2025 |
| Acredome Limited | Strathclyde | 2005 |
| Acrefray Limited | Bridgend | 2025 |
| Acrehale Limited | Bridgend | 2026 |
| Acresbrook Limited | Salford | 1997 |
| Acresgreen Ltd | Stoke-On-Trent | 2020 |
| Acrobat Talent Ltd | Old Windsor | 2025 |
| Acron Music Ltd | London | 2023 |
| Acronis-Partner Ltd | Manchester | 2020 |
| Acropolis Technical Group Limited | Calne | 2023 |
| Across Generations Ltd | London | 2022 |
| Across the Miles Limited | Aylesbury | 2020 |
| Across the Nations Limited | Newtownards | 1994 |
| Across the Pond Productions Limited | London | 2022 |
| Across the World Limited | Bognor Regis | 2006 |
| Acrs Heat Pumps Limited | Evesham | 2012 |
| Acrux Investments Ltd | Blackpool | 2023 |
| Acrylic Pictures Limited | Cardiff | 2010 |
| ACS (Construction Services) Ltd | Hampshire | 1979 |
| ACS Accounting Services Limited | Wokingham | 2004 |
| ACS Business Supplies Ltd | London | 2022 |
| ACS Company Secretaries Limited | Wokingham | 2008 |
| ACS ED Shelf 11 Limited | Birmingham | 2017 |
| ACS ED Shelf 5 Limited | Birmingham | 2020 |
| ACS ED Shelf 7 Limited | Birmingham | 2020 |
| ACS ED Shelf 8 Limited | Birmingham | 2017 |
| ACS Event Services Limited | Poole | 2013 |
| ACS Group of Companies Limited | Poole | 2015 |
| ACS Industrial Doors Limited | Hayes | 2019 |
| ACS Investment Management Ltd | Edinburgh | 2012 |
| ACS Plant Limited | Stockport | 2008 |
| ACS Property Partners Limited | London | 2024 |
| ACS Recruitment Limited | Northampton | 2026 |
| ACS Site Services Limited | Gosport | 2013 |
| ACS Solicitors Ltd. | Wirral | 2010 |
| ACS Staffing Solutions Limited | Northampton | 2023 |
| Acsca One Limited | Llandudno Junction | 2012 |
| Acsca Option Limited | Llandudno Junction | 2012 |
| Acsg Ltd | Kilmarnock | 2025 |
| ACT Clean Limited | London | 2013 |
| ACT Investment Consulting Ltd | Sheffield | 2011 |
| ACT Outdoors Limited | Cardiff | 2011 |
| ACT Sports Limited | Faringdon | 2018 |
| Actegy Health Limited | Bracknell | 2012 |
| Acteon Communication and Learning Limited | Cambridge | 2012 |
| Actfit Ltd | London | 2015 |
| Action 4 Business Limited | Sheffield | 2004 |
| Action Community Resource Development | Hollinwodd | 2003 |
| Action Europe Limited | Shropshire | 1999 |
| Action Express Limited | Milton Keynes | 2000 |
| Action Figured Ltd | Stoke-On-Trent | 2023 |
| Action FM Limited | Harrogate | 2025 |
| Action for Autism Limited | London | 1999 |
| Action for Fathers Limited | Bedfordshire, Flitwick | 2023 |
| Action for Learning Limited | Middlesex | 2007 |
| Action for Lifelong Learning Limited | Eastleigh | 2007 |
| Action Freight Forwarders Limited | Southport | 2014 |
| Action Grandad Limited | Stourbridge | 2023 |
| Action Import and Export Limited | Southport | 2014 |
| Action Stunts UK Limited | Chester | 2022 |
| Action Video Services Ltd | Frinton-On-Sea | 1997 |
| Action Visas Limited | London | 2000 |
| Action Volunteers Limited | Towcester | 2017 |
| Action X Ltd | Bognor Regis | 2022 |
| Action Yemen Limited | Birmingham | 2023 |
| Actionstep Limited | High Wycombe | 2022 |
| Actisense Limited | Poole | 2010 |
| Actius (International) Limited | Leeds | 2011 |
| Activ Sports Group Ltd | Launceston | 2015 |
| ACTIV4 Limited | Shrewsbury | 2004 |
| ACTIV8 (UK) Ltd | Sevenoaks | 2014 |
| Activate Communications Limited | Poynton | 1999 |
| Activated Carbon Ltd | Cheshire | 2015 |
| Activator Brands Limited | Shirebrook | 2005 |
| Activator Products Limited | Shirebrook | 2001 |
| Active Abundance Ltd | London | 2022 |
| Active ARK Outdoors Limited | Carlisle | 2002 |
| Active Building Services Limited | Maidenhead | 2009 |
| Active Career Transition Limited | Kent | 2005 |
| Active Data Cabling Limited | Maidenhead | 2009 |
| Active Digital Limited | London | 2010 |
| Active Door Solutions Limited | Ilford | 2016 |
| Active Education Group Ltd | London | 2011 |
| Active Electrical Limited | Maidenhead | 2007 |
| Active Electricians Limited | Maidenhead | 2007 |
| Active Financial Services Limited | Stockton On Tees | 2015 |
| Active Fleet Solutions Limited | Burton-On-Trent | 2007 |
| Active Heating and Plumbing Services Limited | Maidenhead | 2007 |
| Active Hydraulics Limited | Keighley | 2011 |
| Active Imports Limited | Edinburgh | 2003 |