| Accounting Counts Ltd | Professional & scientific | 2018 |
| Accounts Assist Accountants Limited | Professional & scientific | 2010 |
| Accounts Assist Direct Limited | Professional & scientific | 2013 |
| Ace Blitz Clean Services Limited | Households | 2022 |
| Ace Computing Limited | Information & communication | 2017 |
| Ace Electrical Distributors Limited | Real estate | 1977 |
| Ace Inventories Ltd | Real estate | 2015 |
| Ace Maintenance & Decorators Ltd | Construction | 2025 |
| Ace Premier Properties Limited | Real estate | 2022 |
| Ace Scaffolding Assets Limited | Financial services | 2017 |
| Ace Scaffolding Services (London) Ltd | Construction | 2017 |
| Ace Security and Automation Services Limited | Manufacturing | 2025 |
| Ace Signmakers Limited | Manufacturing | 2009 |
| Acelane Properties Ltd | Real estate | 2025 |
| Aceline Builders Limited | Construction | 1992 |
| Acemart London Limited | Real estate | 2018 |
| Acension Cogf CIC | Other services | 2025 |
| Acer Close Management Company Limited | Households | 2014 |
| ACERTA24 Contractors Limited | Administrative & support | 2023 |
| ACERTA24 Limited | Administrative & support | 2014 |
| Achayathis Catering Limited | Hospitality | 2026 |
| Achieve Professional Services Ltd | Real estate | 2024 |
| ACJ Finance Ltd | Professional & scientific | 2023 |
| ACL Mini Colour Print Limited | Construction | 1959 |
| Acorn AR Ltd | Construction | 2025 |
| Acorn Close Management Company Limited | Households | 2011 |
| Acorn Fertility Ltd | Public administration | 2022 |
| Acorn Street (Hunsdon) Management Company Limited | Households | 2012 |
| Acornedge Property Management Company Limited | Real estate | 1991 |
| ACORNS2OAKS Limited | Education | 2002 |
| Acpink Limited | Wholesale & retail | 2019 |
| Acquired Group Services Limited | Manufacturing | 2009 |
| Acquisition Assist Support Ltd | Other services | 2004 |
| Acre Lane (Brixton) Management Co. Limited | Households | 1999 |
| Acre Park Management Ltd | Households | 2006 |
| Acre-Tri RTM Company Limited | Households | 2022 |
| Acres Property Holdings Ltd | Real estate | 2022 |
| Acres Studios Ltd | Information & communication | 2025 |
| Acrial Ltd | Professional & scientific | 2024 |
| Actagility Limited | Other services | 2008 |
| Action and Motion Ltd | Information & communication | 2025 |
| Action London Limited | Wholesale & retail | 2021 |
| Active Achievers Limited | Education | 2023 |
| Active and Ready Ltd | Real estate | 2026 |
| Active Gadgets CIC | Arts & recreation | 2015 |
| Active Health Tech Ltd | Professional & scientific | 2016 |
| Active House (Newhaven) Ltd | Households | 2024 |
| Active Kids Ltd | Education | 2025 |
| Active Sports Ltd | Education | 2018 |
| ACTIVE4ALL C.I.C. | Education | 2023 |
| ACTIVE62 Company Ltd | Health & social care | 2022 |
| Activiti Consulting Limited | Professional & scientific | 2004 |
| Activitypro Limited | Information & communication | 2017 |
| Acton Main Ltd | Financial services | 2022 |
| Acumen Staffing Management Ltd | Professional & scientific | 2009 |
| Acute Designs Limited | Real estate | 2013 |
| Acync Limited | Information & communication | 2025 |
| Aczone Consultants Ltd | Professional & scientific | 2021 |
| AD Interim Limited | Real estate | 1999 |
| Adair Support Limited | Administrative & support | 2022 |
| Adam & Adam Properties Ltd | Real estate | 2017 |
| Adam Autos Croydon Ltd | Wholesale & retail | 2025 |
| Adam Autos Ltd | Wholesale & retail | 2021 |
| Adam Beck Consultancy Limited | Professional & scientific | 2023 |
| Adam James Hair Limited | Other services | 2022 |
| Adam Stephens Ltd | Information & communication | 2011 |
| Adams Cafe Restaurant Limited | Hospitality | 2016 |
| Adams Dental Practice Limited | Health & social care | 2010 |
| Adamski Builders Ltd | Construction | 2021 |
| Adaptive Care Family Services Ltd | Health & social care | 2020 |
| Add-Ins Scaffolding Service Ltd | Construction | 2024 |
| Addington Palace Golf Club Limited | Arts & recreation | 1951 |
| Addis Estates Ltd | Real estate | 2023 |
| Addiscombe Barbers 1 Ltd | Other services | 2026 |
| Addiscombe DRY Cleaners Ltd | Other services | 2024 |
| Addiscombe Estate PL Limited | Construction | 2019 |
| Addiscombe Fruit & VEG Ltd | Wholesale & retail | 2018 |
| Addiscombe Grillo,S Ltd | Hospitality | 2024 |
| Addiscombe Pizza and Grill Ltd | Hospitality | 2025 |
| Addiscombe UK Limited | Administrative & support | 2021 |
| Addom Ltd | Real estate | 2022 |
| Addon Sports UK Ltd | Wholesale & retail | 2026 |
| Adds Services Ltd | Construction | 2021 |
| Addy Solution 4 U Limited | Other services | 2025 |
| Addy Solutions Limited | Administrative & support | 2018 |
| Adehye Digital Services Limited | Information & communication | 2024 |
| Aden Rose Ltd | Other services | 2025 |
| Adenbuild Construction Ltd | Real estate | 2015 |
| Adeniyi Design Ltd | Manufacturing | 2008 |
| Adeola Abeni Labode Limited | Extraterritorial | 2021 |
| Adeon London Limited | Real estate | 2015 |
| Adept London Services Limited | Administrative & support | 2021 |
| Adepta Digital Services Ltd | Information & communication | 2023 |
| Adepto Property Group IBD (Luton) Limited | Manufacturing | 2017 |
| Adex Healthcare Plus Ltd | Administrative & support | 2015 |
| Adeyemi Property Investments Ltd | Real estate | 2021 |
| ADF Mechanical Services Ltd | Construction | 2009 |
| ADF Scaffolding Ltd | Construction | 2014 |
| Adfenwal Ltd | Administrative & support | 2023 |
| Adfinity Ltd | Information & communication | 2017 |