| Anabel Drivers Ltd | Transport & logistics | 2018 |
| Anasa Luxury Limited | Wholesale & retail | 2025 |
| Anastasi Limited | Hospitality | 2025 |
| Anastasia Cafe Ltd | Hospitality | 2026 |
| Anatcom Limited | Wholesale & retail | 2012 |
| Anchor Management Group Ltd | Wholesale & retail | 2025 |
| Andreev Ltd | Wholesale & retail | 2025 |
| Andrei Cretoiu & Sons Ltd | Transport & logistics | 2018 |
| Andrew Beck Limited | Construction | 2016 |
| Andrew Garner Associates Limited | Other services | 2012 |
| Andrew Last Homes & Construction Limited | Construction | 2021 |
| Andrews of Bedford Limited | Transport & logistics | 2015 |
| Andrews Paving Ltd | Construction | 2020 |
| Andromeda FE Leadership Services Ltd | Professional & scientific | 2022 |
| Andronic Limited | Transport & logistics | 2018 |
| Andrzej Rzasowski Limited | Transport & logistics | 2016 |
| Anduril Software 400 Limited | Information & communication | 1998 |
| Aneis Imaging Limited | Wholesale & retail | 2023 |
| Anga Transport Ltd | Transport & logistics | 2018 |
| Angel Property Developers Ltd | Construction | 2025 |
| Angellica Ltd | Transport & logistics | 2014 |
| Angelo Andrade Ltd | Health & social care | 2025 |
| Angelove UK Ltd | Wholesale & retail | 2025 |
| Anglia Airborne Innovations Limited | Professional & scientific | 2014 |
| Anglo European Marine Limited | Transport & logistics | 2002 |
| Anidata UK Ltd | Wholesale & retail | 2019 |
| Anigraphics Productions Limited | Professional & scientific | 2002 |
| Anirudh Alekhya Ltd | Health & social care | 2023 |
| Anja Simonsen Coaching Ltd | Health & social care | 2025 |
| Anjoy Ltd | Health & social care | 2007 |
| Anlaby Ltd | Real estate | 2025 |
| Anmg Limited | Professional & scientific | 2024 |
| Annabel Salter Limited | Health & social care | 2022 |
| Annaluxda Ltd | Wholesale & retail | 2025 |
| Anode Marketing Limited | Professional & scientific | 2014 |
| Anonat Ltd | Professional & scientific | 2016 |
| Anovadent Limited | Health & social care | 2026 |
| ANP Logistics Ltd | Transport & logistics | 2022 |
| Anrn Enterprises Limited | Real estate | 2019 |
| Anrn Services Ltd | Health & social care | 2023 |
| ANS Aurora Limited | Wholesale & retail | 2025 |
| Ansasoha Holdings Ltd | Financial services | 2023 |
| Ansaw Limited | Professional & scientific | 2010 |
| Antonskivlonoks Ltd | Transport & logistics | 2022 |
| Anwara Limited | Professional & scientific | 2012 |
| Anyglass Limited | Manufacturing | 1996 |
| AOC Trans Limited | Transport & logistics | 2023 |
| AOS Car Sales Limited | Wholesale & retail | 2020 |
| AP Food and Wine Ltd | Wholesale & retail | 2020 |
| AP Smile Hub Limited | Health & social care | 2026 |
| Apauk Leisure Group Ltd | Hospitality | 2021 |
| APC Coaching Ltd | Administrative & support | 2023 |
| Apex Global Real Estate Ltd | Real estate | 2022 |
| Apex Strike Academy Ltd | Arts & recreation | 2025 |
| Apollo Adjustments Limited | Real estate | 2009 |
| App Artist Ltd | Information & communication | 2026 |
| Appletons Catering Ltd | Wholesale & retail | 2026 |
| Appletons Events Ltd | Other services | 2026 |
| Appletons Funfairs Ltd | Arts & recreation | 2026 |
| Appletons Leisure Ltd | Arts & recreation | 2025 |
| Apprenticeship Recruitment Limited | Education | 1991 |
| Apsl Systems Limited | Manufacturing | 2016 |
| APT Care Options Ltd | Administrative & support | 2019 |
| Apvm Solutions Limited | Information & communication | 2025 |
| Aqua Sensory Ltd | Education | 2017 |
| Aquarelle Publishing Limited | Arts & recreation | 2005 |
| Aquarius Mobile Bar Ltd | Hospitality | 2018 |
| Aquatics Installation & Maintenance Ltd | Other services | 2024 |
| AR CCM Limited | Professional & scientific | 2016 |
| AR Plumbing & Heating Rugby Limited | Construction | 2025 |
| AR UK Property Ltd | Real estate | 2020 |
| Arabaswanzy Ltd | Other services | 2023 |
| Arabelle Marine UK Limited | Energy | 2013 |
| Arabelle Services UK Limited | Manufacturing | 2002 |
| Arbour Close Freehold Limited | Households | 2011 |
| ARC (Alexis Read Consulting) Ltd | Professional & scientific | 2012 |
| Arcadia Alive Limited | Professional & scientific | 2000 |
| Arcadia Mews Holdings | Financial services | 2019 |
| Arcani Intelligence Ltd | Professional & scientific | 2024 |
| Archer Digital Images Limited | Professional & scientific | 2015 |
| Archer Rois Limited | Real estate | 2026 |
| Arches Business Centre Management Company Limited | Real estate | 1983 |
| Arches Group Ltd | Financial services | 2026 |
| Arches Lane Autospares Limited | Wholesale & retail | 2009 |
| Architest Ltd | Information & communication | 2025 |
| Arczi Ltd | Transport & logistics | 2025 |
| Ardmore Products Limited | Manufacturing | 2010 |
| Arecki Limited | Administrative & support | 2014 |
| Arewa Bakes N' Treats Limited | Hospitality | 2022 |
| Arihant Foods Ltd | Wholesale & retail | 2020 |
| Arise Expedition Limited | Administrative & support | 2015 |
| Arise Haven Properties Ltd | Real estate | 2025 |
| Arjun Engineering Ltd | Professional & scientific | 2023 |
| ARK Cleaning Solutions Limited | Administrative & support | 2025 |
| ARK Kitchens Online Ltd | Manufacturing | 2024 |
| ARK Sports Coaching Ltd | Education | 2026 |
| Arke Engineering Services Limited | Energy | 2023 |
| Arke Technical Limited | Professional & scientific | 2021 |
| Arkley Commercial Property Limited | Real estate | 2014 |
| Arkwright Ventures Limited | Real estate | 2018 |