| Advanced Lawn Care Limited | Derby | 2009 |
| Advanced Logic Analytics Holdings Limited | Solihull | 2015 |
| Advanced Logic Analytics Limited | Solihull | 2015 |
| Advanced Manufacturing Forum | Jarrow | 2006 |
| Advanced Material Handling Limited | Middlesbrough | 2009 |
| Advanced Medical Aesthetics Academy Ltd | Southall | 2025 |
| Advanced Molecular Vision Limited | Guildford | 2006 |
| Advanced MSK Ltd | Leicester | 2020 |
| Advanced Nanotechnologies LAB Ltd | Lancaster | 2017 |
| Advanced Nurse Aesthetics Limited | Johnstone | 2025 |
| Advanced Project Consultancy Limited | Leyland | 1995 |
| Advanced Rejuvenation London Limited | London | 2023 |
| Advanced Research & Engineering Limited | London | 2003 |
| Advanced Resource Management Limited | Pontypridd | 2006 |
| Advanced Safety Group Ltd | Newcastle Upon Tyne | 2020 |
| Advanced Seating Solutions Ltd | Gosport | 2016 |
| Advanced Security Distribution (NI) Ltd | Cookstown | 2025 |
| Advanced Signal Monitoring Ltd | London | 2007 |
| Advanced Skin Therapy Ltd | Roslin | 2026 |
| Advanced Skincare Medical Aesthetics Ltd | Bathgate | 2021 |
| Advanced Solutions for Trading Ltd | Manchester | 2025 |
| Advanced Solutions(U.K) Ltd | London | 2020 |
| Advanced Spraying Solutions Limited | Basildon | 2022 |
| Advanced Storage Systems Limited | Dundee | 2011 |
| Advanced Systems London Ltd | Borehamwood | 2013 |
| Advanced Technology Promotions Ltd | London | 2019 |
| Advanced Technology Services, UK Limited | Kettering | 2007 |
| Advanced Training Designs Limited | Hassocks | 2014 |
| Advanced Treatments Ltd Ltd | Doncaster | 2022 |
| Advanced Trimarans Limited | London | 2023 |
| Advanced Turf Machinery Limited | Northampton | 1990 |
| Advanced Utility Management Limited | Newcastle Upon Tyne | 2022 |
| Advanced Valeting Centre Limited | Farnborough | 2013 |
| Advanced Vinyl Applications Ltd | Stoke-On-Trent | 2026 |
| Advanced Vision Surveillance Limited | Enfield | 2001 |
| Advanced Wallsend Test Centre Ltd | Wallsend | 2014 |
| Advanced Welding Projects Limited | Coatbridge | 2010 |
| Advanced Wellness Spa Ltd. | Milton Keynes | 2019 |
| Advancedfunding Limited | Hythe | 2025 |
| Advancedit-Services Ltd | Reading | 2012 |
| Advancedlaserscotland Ltd | Paisley | 2026 |
| Advancin 2 Ltd | London | 2019 |
| Advancing Aberystwyth AR Y Blaen Ltd | Aberystwyth | 2016 |
| Advanspec UK Limited | Cockfosters | 2016 |
| Advantage Business Angels Limited | Tenbury Wells | 2016 |
| Advantage Church Ltd | Luton | 2026 |
| Advantage Driver Performance Limited | Beverley | 2025 |
| Advantage Environmental & Construction Ltd | Grays | 2019 |
| Advantage Equity Limited | Edgware | 2022 |
| Advantage Garage Doors Ltd | St. Asaph | 2002 |
| Advantage Global Group UK Ltd | London | 2020 |
| Advantage Personal Training Ltd | Dunstable | 2022 |
| Advantage Printing Solutions Limited | Tynemouth | 2013 |
| Advantage Rail Ltd | Crewe | 2022 |
| Advantage Services Limited | Nottingham | 2020 |
| Advantage Storage & Handling Limited | Cirencester | 2000 |
| Advantage Water Limited | Weybridge | 2017 |
| Advantage-Uk Holdings Ltd | Cirencester | 2018 |
| Advantec Computing Limited | Tenterden | 2011 |
| Advantia Business Solutions Limited | Bridgend | 1996 |
| Advantus Reports Limited | Leicester | 2013 |
| Advectio Limited | Hythe | 2026 |
| Advee Ltd | Widnes | 2017 |
| Advent Capital (Holdings) Ltd | Brighton | 1995 |
| Advent PM Ltd | Slough | 2020 |
| Adventists in the City CIC | Nottingham | 2025 |
| Adventuracam Ltd | London | 2025 |
| Adventure Agnew Limited | Gloucester | 2025 |
| Adventure Arts CIC | Rochdale | 2026 |
| Adventure Cycle Hire Ltd | Milton Keynes | 2019 |
| Adventure Cycle Hire RP Ltd | Milton Keynes | 2024 |
| Adventure Families Limited | Leeds | 2023 |
| Adventure Fur-Ever Limited | Wellingborough | 2022 |
| Adventure Guardians Limited | Southampton | 2016 |
| Adventure Hair,Beauty and Aesthetic Clinic Limited | London | 2013 |
| Adventure Hounds Ltd | Northampton | 2024 |
| Adventure Lane CIC | Rothesay | 2024 |
| Adventure Lounge Ltd | Salford | 2016 |
| Adventure Northumberland Limited | Alnwick | 2013 |
| Adventure Pups Ltd | London | 2025 |
| Adventure Rope Co. Limited | Wadhurst | 2001 |
| Adventure Therapy West Limited | Belleek | 2021 |
| Adventure Velo Ltd | Cirencester | 2022 |
| Adventure Village Limited | Stevenage | 2021 |
| Adventure.I.Am Limited | Brecon | 2023 |
| Adventures Barbers Limited | Croydon | 2019 |
| Adventures With EJ Ltd | London | 2024 |
| Adventuring Within Limited | Sandhurst | 2017 |
| Adventurous Paws Ltd | Eastleigh | 2023 |
| Adverglow Limited | London | 2025 |
| Advertising 99 Ltd | Romford | 2025 |
| Advertising Association Adgreen Ltd | London | 2020 |
| Advertising Association(The) | London | 1926 |
| Advertising Standards Board of Finance Limited(The) | London | 1975 |
| Advertsignment Limited | Ilford | 2023 |
| Advex Ltd | Milton Keynes | 2020 |
| Advice Bedfordshire Community Interest Company | Bedfordshire | 2007 |
| Advice Check Ltd | London | 2018 |
| Advice for Good CIC | Northampton | 2025 |
| Advice for Study Limited | London | 2006 |