| Application Research Ltd | London | 2015 |
| Applications (Uckfield) Holdings Limited | Maresfield | 2014 |
| Applicationz Limited | Bedford | 2014 |
| Applied Chemicals UK Limited | Walsall | 2007 |
| Applied Computer Techniques Ltd | Birmingham | 2014 |
| Applied Equine Behaviour Ltd | Forest Row | 2015 |
| Applied Group Limited | Barnsley | 2021 |
| Applied Influence Consulting Limited | London | 2022 |
| Applied Intelligence Limited | Ty Croes | 2016 |
| Applied Link Bspm Ltd | Reading | 2018 |
| Applied Product Design Ltd | Bristol | 2011 |
| Applied Services Limited | Barnsley | 2022 |
| Applifting Ltd | Doncaster | 2020 |
| Applizmo Limited | Maldon | 2019 |
| APPLY2UNI Limited | London | 2014 |
| Appointai Ltd | Sheffield | 2025 |
| Appointment With MR Yeats Ltd | Southwark | 2009 |
| Appreciative Ltd | London | 2026 |
| Apprentice Employment Agency Limited | Sheffield | 2011 |
| Apprentico Ltd | Esher | 2007 |
| Appropriate Application Limited | Eastbourne | 1995 |
| Appropriate Ltd | London | 2026 |
| Approved Brickwork and Repointing Ltd | Birmingham | 2024 |
| Approved Parcel Delivery Ltd | Wolverhampton | 2023 |
| Approved Protection Ltd | Woodford Green | 2024 |
| Approved Spotless Cleaning Services Limited | Gillingham | 2005 |
| Apps DBA Limited | Middlesex | 2004 |
| Apptician Limited | Poole | 2022 |
| Appy Fleet Limited | Crewe | 2016 |
| APR COV Ltd | Nottingham | 2011 |
| APR Driveway Management Limited | Sevenoaks | 2009 |
| APR Financial Management Limited | Middlesex | 2005 |
| APR Property Management Ltd | Blackwood | 2023 |
| APR Trading Ltd | Cossington | 2012 |
| Apres Aviation Limited | Sutton Coldfield | 2025 |
| Apres Interiors Limited | Sutton Coldfield | 2009 |
| Apres-Tea Ltd | London | 2025 |
| Apricot Computers Limited | Bodmin | 2022 |
| Apricot Consumer Technology Limited | Birmingham | 2012 |
| Apricot Environmental (NI) Limited | Newry | 2003 |
| April 8 UK Limited | London | 2009 |
| April Miller Limited | | 2006 |
| April Yachting Ltd | London | 2020 |
| APRIL68 Ltd | Doncaster | 2026 |
| Aprios Ltd | Reading | 2007 |
| Aprogo Limited | Oxford | 2011 |
| Aproste Ltd | Coventry | 2024 |
| APS EOT Limited | Livingston | 2025 |
| APS Masonry Limited | Burford | 2023 |
| APS Nominees Limited | Aylesbury | 2011 |
| APS Project Solutions Limited | Manchester | 2021 |
| Apsense Ltd | London | 2011 |
| Apsleyhome Limited | Manchester | 1983 |
| Apsm Trade Co., Ltd. | London | 2016 |
| APT Accountancy Ltd | Bolton | 2005 |
| APT Global Fitness Limited | Market Rasen | 2023 |
| APT Manley Limited | London | 2013 |
| APT Trustees Limited | Tunbridge Wells, Kent | 2019 |
| Apt-Gb Ltd | Liskeard | 2015 |
| Aptasort Limited | York | 2014 |
| Aptec IT Solutions Limited | Northampton | 2013 |
| Aptician Limited | London | 2012 |
| Aptm Limited | London | 2022 |
| Aptsm Limited | Manchester | 2015 |
| Aptus Connectivity Limited | Hertford | 2014 |
| Aptus Flow Ltd | Worthing | 2022 |
| Aptus Heat Pumps Limited | Watford | 2012 |
| Aptus Limited | Bolton | 2012 |
| Aptus Plumbing & Heating Limited | Chesterfield | 2013 |
| Apythox Technologies Ltd | Manchester | 2024 |
| AQL (Datacentres) Ltd | Leeds | 2013 |
| AQL (DC Operations) Ltd | Leeds | 2013 |
| Aqonkaal Limited | London | 2011 |
| AQR Properties Limited | Manchester | 2019 |
| AQS (Services) Limited | Southend On Sea | 2007 |
| Aqsa Enterprises Limited | Bolton | 2017 |
| Aqtar Import and Export Co., Ltd | London | 2025 |
| Aqua B Limited | Nottingham | 2013 |
| Aqua B LTM Holdings Limited | Nottingham | 2013 |
| Aqua B Solutions Limited | Nottingham | 2013 |
| Aqua BLU Aesthetics Ltd | Wolverhampton | 2022 |
| Aqua Blue Marine Ltd. | London | 2018 |
| Aqua Blue Seafoods Limited | Trowbridge | 1987 |
| Aqua Clarity Limited | Swaffham | 2010 |
| Aqua Cooling Hire Ltd | Eastleigh | 2018 |
| Aqua Cooling Services Limited | Eastleigh | 2006 |
| Aqua Core Plumbing Services Limited | Gravesend | 2020 |
| Aqua Crystal UK Limited | Stone | 2012 |
| Aqua Design and Leisure Limited | Salisbury | 1993 |
| Aqua Direct Limited | Elmhurst Lichfield | 1997 |
| Aqua Dreamer Ltd | London | 2020 |
| Aqua Felix Ltd | London | 2020 |
| Aqua Fiat Ltd. | Stevenage | 2016 |
| Aqua Guardian Limited | Blackburn | 2018 |
| Aqua Property Holdings Limited | Bath | 2018 |
| Aqua Rail Limited | Skelmersdale | 2012 |
| Aqua Right (UK) Limited | Manchester | 2012 |
| Aqua Right Supplies Limited | Manchester | 2012 |
| Aqua Store Ltd. | Dorchester | 2020 |
| Aqua Tank Systems Limited | Warwickshire | 1999 |