| Alam&Co Ltd | Professional & scientific | 2021 |
| Alamteq Limited | Wholesale & retail | 2017 |
| Alan Chalmers (Chemists) Limited | Wholesale & retail | 2003 |
| Alan Water Ltd | Professional & scientific | 2024 |
| Alastair Merrill Limited | Professional & scientific | 2013 |
| ALB Electricians Ltd | Construction | 2026 |
| ALB Homecare Ltd | Administrative & support | 2023 |
| ALB Skips Ltd | Water & waste | 2019 |
| Albaraka Limited | Professional & scientific | 1999 |
| Albert and BB Investments Limited | Extraterritorial | 2009 |
| Alberto Creative Studio Ltd | Information & communication | 2026 |
| Albin Ltd | Construction | 2024 |
| Alcon Telecom Ltd | Information & communication | 2018 |
| Aldin Accountancy Services Ltd | Professional & scientific | 2019 |
| Aldrich Services Ltd | Transport & logistics | 2022 |
| Aldv Property Management Limited | Real estate | 2010 |
| Aleccy & Co Ltd | Information & communication | 2017 |
| Aleena London Ltd | Wholesale & retail | 2021 |
| Aleenstar Limited | Wholesale & retail | 2023 |
| Alenra Global Ltd | Education | 2025 |
| Alex Cameron Limited | Professional & scientific | 2010 |
| Alex Hair Design Ltd | Other services | 2019 |
| Alex Khan Ltd | Information & communication | 2023 |
| Alex Mcdowell Limited | Information & communication | 2024 |
| Alex Property Group Ltd | Real estate | 2025 |
| Alex Wellesley Wesley Art & Design Limited | Arts & recreation | 2007 |
| Alexander Care (Exeter) Limited | Health & social care | 2020 |
| Alexander Hamilton Chase Ltd | Real estate | 2020 |
| Alexander Hawthorne Asset Ltd | Households | 2021 |
| Alexandra 123 Ltd | Health & social care | 2020 |
| Alexandra Accounting Limited | Professional & scientific | 2016 |
| Alexandra House (Wolverhampton) Limited | Real estate | 2020 |
| Alexandra Park (Maidenhead) Residents Management Company Limited | Households | 2015 |
| Alexealin Ltd | Transport & logistics | 2019 |
| Alexliv Services Ltd | Water & waste | 2019 |
| Alflah Trading UK Ltd | Wholesale & retail | 2024 |
| Alflah UK Ltd | Real estate | 2021 |
| Algeonix Ltd | Construction | 2024 |
| Algorythm Tech Ltd | Information & communication | 2023 |
| Alharamainexpress Ltd | Administrative & support | 2019 |
| Alhussain Limited | Transport & logistics | 2014 |
| ALI & FF Limited | Wholesale & retail | 2024 |
| ALI Baba&Bros Limited | Wholesale & retail | 2024 |
| ALI Catering & Decorations Ltd | Hospitality | 2023 |
| ALI G2 Ltd | Hospitality | 2019 |
| ALI Hairdressers (Slough) Ltd | Other services | 2019 |
| ALI Home Bargain Ltd | Wholesale & retail | 2024 |
| ALI Home Service Limited | Real estate | 2024 |
| ALI Ijaz Finance Ltd | Professional & scientific | 2018 |
| ALI Logistics Ltd | Transport & logistics | 2025 |
| ALI Yago Ltd | Other services | 2021 |
| Ali's Emporium Limited | Wholesale & retail | 2024 |
| Alia Family Chilya T/ a the Cockerel Ltd | Hospitality | 2020 |
| Alice Trade & Logistics Ltd | Transport & logistics | 2024 |
| Alice Trade Experts Ltd | Transport & logistics | 2024 |
| Alico Petroleum Ltd | Administrative & support | 2016 |
| Alidor RAS Limited | Transport & logistics | 2026 |
| Alif Productions Ltd | Wholesale & retail | 2024 |
| Alight Energy UK Limited | Energy | 2023 |
| Alight Property Ltd | Real estate | 2025 |
| Alight Stingray Holding Limited | Energy | 2025 |
| Alight UK BTM II Limited | Energy | 2023 |
| Alight UK BTM1 Limited | Energy | 2023 |
| Align Care Plus UK Ltd | Health & social care | 2023 |
| Align Care Services Ltd | Administrative & support | 2024 |
| Aligned Advice Ltd | Financial services | 2025 |
| Aligner Studio Global Ltd | Manufacturing | 2026 |
| Alimar Transport Limited | Transport & logistics | 2015 |
| Alina 123 Ltd | Health & social care | 2020 |
| Alinmead Limited | Manufacturing | 1999 |
| Alioliotui Services Ltd | Education | 2024 |
| Alipari UK Sales Ltd | Wholesale & retail | 2025 |
| Alisha (London) Ltd | Health & social care | 2011 |
| Alisha Hussain Ltd | Wholesale & retail | 2024 |
| Alisha Thakrar KA Consulting Ltd | Professional & scientific | 2025 |
| Alisha's Kitchen Ltd | Hospitality | 2025 |
| Aliships Commerce Ltd | Wholesale & retail | 2025 |
| Alison Lucinda Richardson Limited | Extraterritorial | 2025 |
| Alitech Solutions Ltd | Administrative & support | 2025 |
| Alittz Ltd | Wholesale & retail | 2012 |
| Alivecor Limited | Health & social care | 2013 |
| Alka Sharma Estates Ltd | Real estate | 2023 |
| Alkasiri Properties Ltd | Financial services | 2025 |
| Alkay Traders Ltd | Wholesale & retail | 2025 |
| Alkhalidia Group Holding Ltd | Real estate | 2023 |
| ALL & More Consulting Ltd | Professional & scientific | 2025 |
| ALL About Construction Ltd | Construction | 2019 |
| ALL Available Limited | Wholesale & retail | 2023 |
| ALL Awan Limited | Wholesale & retail | 2018 |
| ALL Budget Cars Ltd | Wholesale & retail | 2025 |
| ALL Classic Car Parts Ltd | Wholesale & retail | 2016 |
| ALL Elite Marketing Ltd | Wholesale & retail | 2025 |
| ALL Heart Homecare Services Limited | Administrative & support | 2019 |
| ALL Junks Ltd | Transport & logistics | 2026 |
| ALL Kind Care Services Limited | Health & social care | 2025 |
| ALL OUT Companies Ltd | Arts & recreation | 2020 |
| ALL OUT Crew Ltd | Transport & logistics | 2025 |
| ALL Prestige Ltd | Wholesale & retail | 2025 |
| ALL Pure Ltd | Wholesale & retail | 2024 |
| ALL Real Deal Limited | Wholesale & retail | 2026 |