| A-Connect Solution (UK) Limited | London | 2009 |
| A-Count on ME Ltd | Nuneaton | 2019 |
| A-Counting Genie Ltd | Great Whelnetham | 2020 |
| A-Craft Limited | King'S Lynn | 2026 |
| A-Creative Limited | Hornchurch | 2002 |
| A-Cubed Design Ltd. | Glasgow | 2005 |
| A-Data Limited | Portsmouth | 2003 |
| A-Davis Solutions Ltd | Canvey Island | 2022 |
| A-Did Marketing Limited | London | 2022 |
| A-Dsp Consulting Limited | Plymouth | 2013 |
| A-Fab Signs Limited | Chichester | 2014 |
| A-Ffinity Europe Ltd | Teddington | 2015 |
| A-Fit : Anglo-French Interim Transition Limited | London | 2024 |
| A-Frame Agency UK Limited | Southwark | 2021 |
| A-Frame Futures Ltd | London | 2025 |
| A-G-Design Ltd | Worcester Park | 2022 |
| A-Game Advisory Limited | Buckhurst Hill | 2024 |
| A-Gas (ORB) Limited | Bristol | 2011 |
| A-Gas Investments Limited | Bristol | 2006 |
| A-Grade Interiors Design Consultancy Ltd | Nottingham | 2023 |
| A-Ha! Distribution Limited | Ilkley | 2013 |
| A-Hdw S.L. Ltd | London | 2018 |
| A-Hh Solutions Limited | Oldham | 2023 |
| A-I Bioprocessing Limited | Newport Pagnell | 2025 |
| A-Kounts Connect Limited | Birmingham | 2015 |
| A-L Carruth Ltd | Bury St. Edmunds | 2016 |
| A-L Mechanical Engineering Services Limited | Chesterfield | 2022 |
| A-Leaf INT. UK Ltd | Ipswich | 2022 |
| A-Legal Limited | Sutton | 2022 |
| A-Life Ventures Ltd | Canvey Island | 2025 |
| A-Lign Microscopes Limited | Market Lavington | 2018 |
| A-List Accounting Ltd | Waterlooville | 2025 |
| A-Lister Consulting Limited | Stockport | 2012 |
| A-M Studio Ltd | Bath | 2016 |
| A-M-S Business Solutions (UK) Ltd | Lytham St.Annes | 2022 |
| A-Mc Pipeshop Engineering Ltd | Irvine | 2026 |
| A-Met Metrology Ltd | Hereford | 2013 |
| A-Modelling Solutions Ltd | Guildford | 2019 |
| A-Mty FEA Ltd | Derby | 2024 |
| A-Nd Design Studio Ltd | Stockport | 2018 |
| A-Ndt Inspections Limited | Glasgow | 2015 |
| A-Net Professionals Limited | Birmingham | 2024 |
| A-Nur Consultancy Limited | Harlow | 2025 |
| A-Okdigital Ltd | London | 2026 |
| A-P Studios Ltd | Bolton | 2022 |
| A-Pedwar Cyfyngedig | Caernarfon | 2008 |
| A-Photo Limited | Epsom | 2009 |
| A-Plus Ideation Agency Ltd | London | 2017 |
| A-Plus Legal Assist Ltd | Heywood | 2022 |
| A-Plus Trading Limited | Sheffield | 2011 |
| A-Project Design Limited | London | 2013 |
| A-Projects Ltd | London | 2008 |
| A-Rated Energy Services Limited | High Peak | 2023 |
| A-Roads Investments Limited | London | 2006 |
| A-Ron Services Kent Limited | Gillingham | 2018 |
| A-S-4-U Limited | Kessingland | 2011 |
| A-S-J Engineering Solutions Ltd | Market Rasen | 2019 |
| A-Safe Limited | Elland | 1999 |
| A-Scan Weld Inspection Ltd | Kinross | 2017 |
| A-Sheore Limited | Leeds | 2022 |
| A-Shire Holdings Limited | Alsager | 2024 |
| A-Side Design Limited | Redruth | 2015 |
| A-Side Publishing Limited | London | 2001 |
| A-Sides Copywriting Limited | London | 2025 |
| A-Sin Creative Group Ltd | London | 2023 |
| A-Smood Management Consulting Ltd | London | 2017 |
| A-Social-Life Ltd | London | 2024 |
| A-Spire Business Partners Ltd | Middlesex | 2003 |
| A-Square Corporation Ltd | Cheadle | 2013 |
| A-Squared (A2) Ltd | London | 2025 |
| A-Squared Consultancy Services Limited | Manchester | 2018 |
| A-Squared Engineering Ltd | Perth | 2018 |
| A-Squared Studio Engineers Ltd | Benfleet | 2014 |
| A-Star Accounting Limited | Aldershot | 2026 |
| A-Star Professional Limited | Hemel Hempstead | 2015 |
| A-Strat Advisory Limited | London | 2013 |
| A-Team Marine Ltd | London | 2026 |
| A-Team Outsourcing Limited | Bedford | 2025 |
| A-Tec Aerospace Ltd | Chester | 2026 |
| A-Tec Engineering (U.K.) Limited | Manchester | 2003 |
| A-Tech Architectural Design Ltd | Buxton | 2009 |
| A-Tech Industries Ltd | Newton Aycliffe | 2012 |
| A-Tech Offshore Limited | Stroud | 2014 |
| A-Techs Wind Limited | York | 2023 |
| A-Teck Surveys Ltd | Sale | 2023 |
| A-Tek Design Ltd | Nottingham | 2024 |
| A-Tek Engineering Limited | Milton Keynes | 2020 |
| A-Tex International Co., Limited | Grangetown Cardiff | 2006 |
| A-Track Consult Ltd | Dowlais | 2025 |
| A-Up Business Planning and Design Ltd | Halifax | 2014 |
| A-V-A Blinds & Shutters London Ltd | London | 2025 |
| A-Vision UK Ltd | Kidderminster | 2007 |
| A-Way Online Ltd | Redditch | 2023 |
| A-Way UP Ltd | Romford | 2023 |
| A-Z Management 001 Ltd | Birmingham | 2021 |
| A-Z Accountancy & Taxation Services Ltd | London | 2020 |
| A-Z Accountancy Ltd | Waltham Cross | 2019 |
| A-Z Agencies & Accountants Ltd | London | 1995 |
| A-Z Animals Limited | Dorking | 1993 |
| A-Z Bookkeeping & Accounting Ltd | Kettering | 2022 |