| Affirmative Assets Limited | Financial services | 2020 |
| Affordable Rental Homes Ltd | Real estate | 2025 |
| Affordables INT Ltd | Wholesale & retail | 2025 |
| Afili Ltd | Wholesale & retail | 2024 |
| Afr-Ix Telecom Ltd | Information & communication | 2019 |
| Africa Exports & Imports Pavilions Ltd | Wholesale & retail | 2022 |
| Africa Minerals and Miners Centre Ltd | Mining & quarrying | 2023 |
| Agesico Components Co., Ltd | Wholesale & retail | 2024 |
| Agileavtar Ltd | Information & communication | 2021 |
| AGN Holdings Ltd | Financial services | 2019 |
| Agni Engineering Services Ltd | Professional & scientific | 2022 |
| Agni Suria UK Limited | Financial services | 2023 |
| Agriflo Ltd | Agriculture & fishing | 2020 |
| AHB Consultancy Services Limited | Professional & scientific | 2025 |
| Ahbay Investments Ltd | Real estate | 2017 |
| Ahmed LA Support Limited | Transport & logistics | 2025 |
| Ahmeds Estate Ltd | Real estate | 2022 |
| Ahmet Melih Uzun Ltd | Wholesale & retail | 2023 |
| AI Entertainment Ltd | Information & communication | 2025 |
| Aibac Properties (UK) Ltd | Manufacturing | 2013 |
| Aiconnexion Services Ltd | Administrative & support | 2026 |
| Aidakuk Investment Limited | Real estate | 2016 |
| AIM High Construction Ltd | Construction | 2018 |
| AIM Opulent Limited | Financial services | 2020 |
| Aimia Limited | Real estate | 2025 |
| Ainro Ltd | Construction | 2014 |
| Aipayex Ltd | Administrative & support | 2023 |
| Air 2 O Limited | Construction | 2009 |
| Airbookings UK Ltd | Transport & logistics | 2011 |
| Airglow Ltd | Information & communication | 2011 |
| Airo Cars Ltd. | Transport & logistics | 2014 |
| Airport Systems Limited | Administrative & support | 2022 |
| Aishree Imports Limited | Real estate | 2022 |
| AJ Beauty Limited | Other services | 2024 |
| AJ UK Property Ltd | Real estate | 2024 |
| Ajdcs Limited | Professional & scientific | 2011 |
| AJJ Acquisitions Limited | Real estate | 2021 |
| AK Care Network Ltd | Health & social care | 2025 |
| AK Traders Ltd | Wholesale & retail | 2016 |
| Akan Brown Ltd | Professional & scientific | 2021 |
| Akar London Ltd | Hospitality | 2023 |
| Akenstone International Limited | Wholesale & retail | 1991 |
| AKF Property Investments Limited | Real estate | 2023 |
| Akinreacts Ltd | Information & communication | 2023 |
| Akkad Property Limited | Households | 2019 |
| AKM Plumbing & Heating Services Limited | Construction | 2017 |
| Akras Solutions Limited | Health & social care | 2014 |
| Akshardham Properties Limited | Real estate | 2023 |
| Akshi Limited | Professional & scientific | 2015 |
| AL-BARR-79 Ltd | Wholesale & retail | 2025 |
| Al-Laymoun Ltd | Professional & scientific | 2024 |
| ALA Packaging Co., Ltd | Extraterritorial | 2020 |
| Alan Accountancy Ltd | Professional & scientific | 2014 |
| Alango Events Consulting International Ltd | Information & communication | 2018 |
| Albany Home Improvements Limited | Construction | 2018 |
| ALC Signature Project Ltd | Construction | 2025 |
| Aldons and Co Building and Maintenance Ltd | Construction | 2022 |
| Aldwych (Harrow) Limited | Hospitality | 2004 |
| Aldwych Leisure Limited | Hospitality | 1996 |
| Aleana Limited | Real estate | 2024 |
| Alert-Now Ltd | Administrative & support | 2026 |
| Alex CNC Industry Co., Ltd | Wholesale & retail | 2023 |
| Alex Spencer Design Ltd | Professional & scientific | 2011 |
| Alexander and Bardan Ltd | Hospitality | 2025 |
| Alfa Cars Transport Logistics Ltd | Transport & logistics | 2017 |
| ALI and Brothers Ltd | Other services | 2019 |
| Aligned IP Limited | Other services | 2020 |
| Alim Caterers Limited | Hospitality | 1986 |
| Alim Investments Limited | Hospitality | 1985 |
| Alipe Services Ltd | Health & social care | 2021 |
| Alisa Trades Ltd | Financial services | 2026 |
| Alison Roberts Limited | Arts & recreation | 2003 |
| ALL Aboard Ship Ahoy Limited | Administrative & support | 2019 |
| ALL Grease Gone Ltd | Administrative & support | 2020 |
| ALL Links Chauffeur Drive Ltd | Transport & logistics | 2011 |
| ALL Point Installations Ltd | Construction | 2012 |
| ALL Roofing Services Ltd | Construction | 2025 |
| ALL Trees (Gatwick) Limited | Administrative & support | 2018 |
| ALL Weather Painting & Decorating Limited | Construction | 2022 |
| ALL Weather Roofing & General Building Limited | Construction | 2017 |
| ALL Weather Roofing and Building Limited | Construction | 2025 |
| ALL Your Dance Needs Limited | Arts & recreation | 2000 |
| All-In-One Digital Solutions Ltd | Wholesale & retail | 2024 |
| All-Tec Recruitment Ltd | Administrative & support | 2023 |
| Allabouttheoak Ltd | Hospitality | 2020 |
| Allambie Enterprises Limited | Health & social care | 2001 |
| Alliance Accountancy Services Ltd | Professional & scientific | 2023 |
| Alliance Roofing & Building Limited | Construction | 2020 |
| Allied Antz Ltd | Manufacturing | 2021 |
| Allow Yourself to Grow Limited | Information & communication | 2025 |
| Allsop Durn LLP | | 2020 |
| Allsop Durn Solicitors Limited | Professional & scientific | 2026 |
| Allways Roofing & Guttering Limited | Construction | 2021 |
| Allwyn Network Limited | Information & communication | 2013 |
| Alma Lusa Ltd | Hospitality | 2016 |
| Alpha Care Consultants Ltd | Health & social care | 2025 |
| Alphabet Security Services Limited | Administrative & support | 2023 |
| Alpine Driveways and Drainage Limited | Construction | 2023 |
| Alpine Driveways and Resin Limited | Construction | 2025 |
| Alpine Driveways and Roofing Limited | Construction | 2023 |