| ANY Services Ltd | Hospitality | 2026 |
| Anya Services Ltd | Construction | 2024 |
| Anything Property Group Ltd | Households | 2025 |
| AP Consultare Ltd | Extraterritorial | 2018 |
| AP Servicing and Repairs Ltd | Wholesale & retail | 2018 |
| Ap&Co. Decor Ltd | Construction | 2026 |
| Apex Construction and Electrical Ltd | Construction | 2021 |
| Apex Consultancy Limited | Professional & scientific | 2025 |
| Apex Creative Ltd | Professional & scientific | 2023 |
| Apex Electronic Repairs Limited | Wholesale & retail | 2023 |
| APL Properties UK Ltd | Real estate | 2022 |
| Appex Alliance Limited | Construction | 2014 |
| Approvemydocs Ltd | Information & communication | 2013 |
| Apps in My Pocket Ltd | Information & communication | 2008 |
| APT Technologies Limited | Information & communication | 2011 |
| Aptolibero Limited | Real estate | 2014 |
| Aqbamb Ltd | Real estate | 2026 |
| Aqeeli Holding Limited | Financial services | 2024 |
| Aqua Flame Ltd | Construction | 2012 |
| Aqua Homes Limited | Construction | 2018 |
| Aquaphysio Limited | Health & social care | 2011 |
| Aqura Ltd | Manufacturing | 2026 |
| AR Associates Ltd | Financial services | 2016 |
| AR Site Management Ltd | Professional & scientific | 2014 |
| ARA Projects Limited | Construction | 2022 |
| Arab Medico Ltd | Information & communication | 2021 |
| Arabian Rain Limited | Hospitality | 2024 |
| Arain Builders Ltd | Construction | 2022 |
| Arborista Limited | Agriculture & fishing | 2020 |
| Arborista+ Ltd | Agriculture & fishing | 2025 |
| Arcadie DE Niche London Limited | Wholesale & retail | 2025 |
| Archviz Studio Ltd | Professional & scientific | 2026 |
| Ardell Living Ltd | Real estate | 2026 |
| Arekipa Ltd | Information & communication | 2018 |
| Arena Food and Wine Ltd | Wholesale & retail | 2025 |
| Argcm Limited | Other services | 2023 |
| Arham Estate Ltd | Real estate | 2021 |
| Arhan Foods UK Ltd | Hospitality | 2025 |
| Ariana AWR UK Ltd | Wholesale & retail | 2019 |
| Arise Robotics Ltd | Information & communication | 2025 |
| Aristocats Pet Minding Limited | Other services | 2013 |
| Aristotle Invest Ltd | Real estate | 2019 |
| Arjan Engineering Consultants UK Ltd | Construction | 2023 |
| ARK Capitalinvest Ltd | Real estate | 2025 |
| Arkley Padel Limited | Wholesale & retail | 2025 |
| Arma Traders Ltd | Wholesale & retail | 2016 |
| Armd International Limited | Wholesale & retail | 2010 |
| Aroma Galleria Ltd | Manufacturing | 2024 |
| Arpo Ltd | Information & communication | 2022 |
| Arrive Fast Ltd | Hospitality | 2018 |
| Arsab Property Investment Ltd | Real estate | 2024 |
| Arte Labs Limited | Professional & scientific | 2017 |
| Arti Interiors Ltd | Construction | 2014 |
| Artviber Limited | Arts & recreation | 2021 |
| Arun Lodge Residential Ltd | Health & social care | 2025 |
| Aryss Ltd | Construction | 2019 |
| AS Construction and Building Limited | Construction | 2017 |
| AS Prime Properties Ltd | Real estate | 2020 |
| ASA London Trading Ltd | Construction | 2022 |
| Asas Excellence for Consultancy Ltd | Professional & scientific | 2025 |
| ASAS7 Ltd | Wholesale & retail | 2025 |
| Ascape Development Ltd | Professional & scientific | 2023 |
| Ascape LLP | | 2015 |
| Ascent Strategies Ltd | Professional & scientific | 2025 |
| Ascot Property Limited | Financial services | 2004 |
| ASH Minicab Services Ltd | Transport & logistics | 2019 |
| Ashbourne Probate Ltd | Professional & scientific | 2016 |
| Ashbury Homeware Ltd | Wholesale & retail | 2025 |
| Ashihara Karate London Limited | Extraterritorial | 2021 |
| Ashley Home Interiors Ltd | Professional & scientific | 2022 |
| Asho Limited | Health & social care | 2009 |
| Ashraf Halal Meat & Grocery Limited | Wholesale & retail | 2013 |
| Ashraf Traders Limited | Wholesale & retail | 2015 |
| Ashtead & Epsom Bespoke Builders Ltd | Construction | 2025 |
| Ashtel UK PVT Ltd | Wholesale & retail | 2020 |
| Asir Trading Ltd | Transport & logistics | 2022 |
| ASJ Private Ltd | Hospitality | 2022 |
| ASK ME Logistics Limited | Transport & logistics | 2018 |
| ASK Pantry Ltd | Administrative & support | 2016 |
| ASK Sources Ltd | Construction | 2025 |
| ASK UK Properties Ltd | Real estate | 2020 |
| Asos Legal Ltd | Professional & scientific | 2026 |
| ASR Enterprise Ltd | Wholesale & retail | 2026 |
| Assad Trading Ltd | Transport & logistics | 2024 |
| Assets Holds Ltd | Financial services | 2025 |
| Assets Investments Limited | Hospitality | 2022 |
| Assets Mall Ltd | Hospitality | 2020 |
| Assets Property Investment Ltd | Real estate | 2025 |
| Assured Future Energy Partners Limited | Professional & scientific | 2025 |
| AST Mobiles and Accessories Ltd | Wholesale & retail | 2025 |
| Astar Business Advisors Limited | Professional & scientific | 2016 |
| Asterion Diagnostics Ltd | Health & social care | 2014 |
| Astontrend Limited | Information & communication | 2015 |
| Astor Solutions Ltd | Construction | 2014 |
| Astrobird Ltd | Professional & scientific | 2019 |
| ASY Properties Ltd | Real estate | 2018 |
| ASYA23 Ltd | Manufacturing | 2025 |
| AT Planning Limited | Construction | 2015 |
| ATC Traders Ltd | Education | 2021 |
| Athar Investments Ltd | Real estate | 2021 |