| Alpha Homes Management Limited | Real estate | 2024 |
| Alpha Inspired Ltd | Extraterritorial | 2023 |
| Alpha Media Rigging Ltd | Construction | 2018 |
| Alpha Production House Limited | Information & communication | 2019 |
| Alpha Recovery and Breakdown Ltd | Administrative & support | 2025 |
| Alpha Recruitment Ltd | Administrative & support | 2026 |
| Alpha Romic Limited | Health & social care | 2014 |
| Alpha Saaz Ltd | Transport & logistics | 2022 |
| Alpha Scooters Limited | Administrative & support | 2024 |
| Alpha Star Logistics Limited | Transport & logistics | 2016 |
| Alpha Team Ltd | Administrative & support | 2024 |
| Alpha Trio Fleet Ltd | Wholesale & retail | 2025 |
| Alphadizenab Limited | Other services | 2017 |
| Alphaframe AI Ltd | Information & communication | 2025 |
| Alphald Ltd | Wholesale & retail | 2025 |
| Alphamax Digital Services Limited | Professional & scientific | 2024 |
| Alphamax Security Limited | Administrative & support | 2024 |
| Alpi Tech Ltd | Wholesale & retail | 2024 |
| Alrai Applied Psychology Limited | Health & social care | 2017 |
| Alsaffa Ltd | Hospitality | 2023 |
| Alsap Ltd | Professional & scientific | 2022 |
| Alseerra’S Limited | Information & communication | 2026 |
| Alsk Limited | Professional & scientific | 2023 |
| Alss Trans Limited | Transport & logistics | 2015 |
| Altcoin Trades Ltd | Financial services | 2014 |
| Altec Facades Ltd | Construction | 2022 |
| Altenmark Limited | Real estate | 1994 |
| Alterergo Limited | Health & social care | 2020 |
| Althorp Medcare Limited | Health & social care | 2026 |
| Altijara Ltd | Wholesale & retail | 2025 |
| Altura Real Estate Ltd | Real estate | 2026 |
| Alumicore Ltd | Wholesale & retail | 2025 |
| Alupoaei Invest Ltd | Transport & logistics | 2022 |
| Alvastone Limited | Manufacturing | 2023 |
| Alvi & BSS Ltd | Wholesale & retail | 2020 |
| Alvi and Sons Limited | Wholesale & retail | 2020 |
| Alxonic Ltd | Information & communication | 2025 |
| Alyen Ltd | Information & communication | 2025 |
| Alynconstruction Limited | Construction | 2022 |
| Alza Motors UK Ltd | Wholesale & retail | 2017 |
| Alzi Construct Limited | Construction | 2020 |
| AM Brickwork Ltd | Construction | 2024 |
| AM Build Solutions Ltd | Construction | 2025 |
| AM Builders (Luton) Limited | Construction | 2012 |
| AM Davies Engineering Ltd | Professional & scientific | 2017 |
| AM Digital Consulting Ltd | Administrative & support | 2026 |
| AM Distilling Ltd | Manufacturing | 2018 |
| AM Electronics Limited | Wholesale & retail | 2024 |
| AM HR & Wellness Consultancy Ltd | Wholesale & retail | 2025 |
| AM Hygiene and Therapy Limited | Health & social care | 2016 |
| AM Jewellers Ltd | Wholesale & retail | 2025 |
| AM Luton Limited | Transport & logistics | 2024 |
| AM Mall Ltd | Wholesale & retail | 2026 |
| AM Plumbing and Heating Services Limited | Construction | 2024 |
| AM Precious Metals Ltd | Wholesale & retail | 2025 |
| AM Properties & Holdings Ltd. | Real estate | 2021 |
| AM Security and Facility Managment Ltd | Administrative & support | 2026 |
| AM Surgical Ltd | Health & social care | 2020 |
| AM3 Properties Limited | Construction | 2021 |
| AMA Investment Limited | Real estate | 2013 |
| Amaan Eco Limited | Construction | 2025 |
| Amaanah Ventures UK Ltd | Hospitality | 2026 |
| Amadumi Electrical Ltd | Construction | 2018 |
| Amal Travels UK Ltd | Transport & logistics | 2024 |
| Amal-Pharma Limited | Wholesale & retail | 2026 |
| Amalmaria Ltd | Wholesale & retail | 2025 |
| Aman Retailers Limited | Wholesale & retail | 2023 |
| Aman Sultan Ltd | Administrative & support | 2026 |
| Amanah Growth Partners Ltd | Professional & scientific | 2025 |
| Amandeep 1 Limited | Construction | 2020 |
| Amaniter Ltd | Professional & scientific | 2019 |
| Amar Contracting Limited | Construction | 2016 |
| AMAR22 Properties Ltd | Real estate | 2024 |
| Amarkable Limited | Wholesale & retail | 2025 |
| Amarro Trading Ltd | Wholesale & retail | 2026 |
| Amaryllis Coaching and Leadership Advisory Services Ltd | Administrative & support | 2022 |
| Amaz Chauffeurs Ltd | Transport & logistics | 2026 |
| Amaze Impacts Limited | Information & communication | 2025 |
| Amazing Store Ltd | Wholesale & retail | 2024 |
| Amazinghope Services Ltd | Health & social care | 2025 |
| Amazon Basin Aquatics (UK) Ltd | Wholesale & retail | 2019 |
| Amazox Ltd | Wholesale & retail | 2025 |
| Amazys Goods & Services Ltd | Administrative & support | 2025 |
| AMB Housing Services Ltd | Real estate | 2026 |
| AMB Import & Export Ltd | Wholesale & retail | 2025 |
| Amba Beds Ltd | Hospitality | 2024 |
| Ambaso Properties Limited | Construction | 2018 |
| Ambels Castle Limited | Hospitality | 2021 |
| Amber Accounts Advisory Ltd | Professional & scientific | 2026 |
| Amber Estates Luton Ltd | Administrative & support | 2017 |
| Amber Gold Limited | Professional & scientific | 2008 |
| Amber Publishing Ltd | Information & communication | 2021 |
| Amber Skin Clinic & Spa Ltd | Other services | 2025 |
| Amber Valley Jiu-Jitsu Ltd | Arts & recreation | 2024 |
| Ambergreen Health & Social Care Ltd | Health & social care | 2013 |
| Amberleigh Events Management Ltd | Hospitality | 2025 |
| Amberleigh Gardens Ltd | Hospitality | 2025 |
| Amberleigh Gardens Marquee Wedding Venue Ltd | Hospitality | 2025 |
| Amberyan Services Ltd | Health & social care | 2016 |
| Ambiaco Limited | Construction | 2025 |