| Lsfp Limited | Professional & scientific | 2022 |
| LT Film FX Limited | Arts & recreation | 2022 |
| LT Radiology Limited | Health & social care | 2015 |
| LU LU Laser Clinic Ltd | Other services | 2024 |
| Lucy Alexandra Batt Limited | Arts & recreation | 2013 |
| Lucy Fyfe Ltd. | Information & communication | 2003 |
| Lukas Plant Ltd | Manufacturing | 2014 |
| Luke's Heating & Plumbing Ltd | Construction | 2023 |
| Lullioo Global Ltd | Wholesale & retail | 2026 |
| Lulu Mart Ltd | Wholesale & retail | 2025 |
| Lumicera Technologies Ltd | Manufacturing | 2025 |
| Luminar Energy Investment and Trading Ltd | Energy | 2026 |
| Lumino Films Ltd | Information & communication | 2012 |
| Luna DE Casanova Holdings Ltd | Financial services | 2017 |
| Luna DE Casanova Limited | Professional & scientific | 2017 |
| Luna Terra Investments Limited | Households | 2025 |
| Luna's Tail Ltd | Wholesale & retail | 2026 |
| Lunn Consultancy Ltd | Administrative & support | 2024 |
| Lupasoft Ltd | Information & communication | 2026 |
| Lupfaw 374 Limited | Hospitality | 2013 |
| Lupfaw 494 Limited | Extraterritorial | 2018 |
| Lush and Green Limited | Wholesale & retail | 2011 |
| Lustrum Investments Limited | Financial services | 2021 |
| Luvyum Ltd | Professional & scientific | 2020 |
| LUX Health Consultancy Ltd | Health & social care | 2025 |
| Luxford Interiors Ltd | Professional & scientific | 2018 |
| Luxtronic Ltd | Manufacturing | 1997 |
| Luxury Lawns AGS Limited | Professional & scientific | 2015 |
| Luxury Pods Ltd | Construction | 2022 |
| Luxury Property Maintenance London Ltd | Construction | 2021 |
| LVC Assets & Management Ltd | Real estate | 2023 |
| Lyall Willis & Co., Limited | Wholesale & retail | 2019 |
| Lychee Studios Ltd | Professional & scientific | 2021 |
| Lyndhurst Sevenoaks Limited | Other services | 2019 |
| Lynton Services Mayfair (1994) Limited | Manufacturing | 1994 |
| Lyos Ltd | Information & communication | 2018 |
| M & a UK Properties Ltd | Real estate | 2019 |
| M & B Site Services Ltd | Construction | 2026 |
| M & C Consulting Ltd | Professional & scientific | 2017 |
| M & S Develops Ltd | Construction | 2021 |
| M & T Logistics Limited | Transport & logistics | 2010 |
| M Cooper Services Ltd | Professional & scientific | 2025 |
| M Dawson Property Services Ltd | Households | 2024 |
| M Ellis Electrical Limited | Construction | 1997 |
| M J Gill Electrical Services Limited | Construction | 2006 |
| M Sage Limited | Wholesale & retail | 2006 |
| M South Professional Services Limited | Professional & scientific | 2016 |
| M Space Serviced Offices Limited | Real estate | 2020 |
| M&A Mechanical Engineering Ltd | Construction | 2024 |
| M&F Tech Ltd | Professional & scientific | 2023 |
| M&G Prime Premium Services Ltd | Administrative & support | 2023 |
| M&L Landscapes Ltd | Administrative & support | 2025 |
| M. Allen Heating & Plumbing Limited | Construction | 2015 |
| M.Ashleyproperties Ltd | Real estate | 2025 |
| M.K. Building Contractors Limited | Construction | 1990 |
| M.S. Land Recovery Ltd | Administrative & support | 2022 |
| M19 Investments Ltd | Financial services | 2026 |
| Maar Ventures Ltd | Real estate | 2023 |
| Macbrog Ltd | Construction | 2023 |
| Macdonald Consultants Limited | Professional & scientific | 2009 |
| Machen Associates Limited | Administrative & support | 2002 |
| Machyle Limited | Health & social care | 2010 |
| Mack-Build Ltd | Construction | 2018 |
| Macwell Group Limited | Extraterritorial | 2010 |
| MAD About Pets Services Ltd | Other services | 2025 |
| Made by Jemima Ltd | Wholesale & retail | 2026 |
| Made for Health Limited | Professional & scientific | 2022 |
| Madgeco Ltd | Professional & scientific | 2025 |
| MAG Property Limited | Real estate | 2018 |
| Magic Publications Ltd | Real estate | 2023 |
| Magichearing.Ai Ltd | Information & communication | 2026 |
| Magrathea Ventures Ltd | Professional & scientific | 2023 |
| Mahek Vara Foundation | Other services | 2019 |
| Mahyoshana Enterprises Limited | Wholesale & retail | 2017 |
| Maiden Strategy Ltd | Extraterritorial | 2026 |
| Maidstone Sports Cars Limited | Manufacturing | 1998 |
| Maidstone Symphony Orchestra Limited | Arts & recreation | 2017 |
| Main Nickolls LLP | | 2020 |
| Mainstay Media LLP | | 2018 |
| Maison Burton Limited | Real estate | 2001 |
| Maja Accommodation UK Ltd | Construction | 2026 |
| Major Investment Group Ltd | Construction | 2021 |
| Make Believe Islington Ltd | Arts & recreation | 2025 |
| Make Wood Good Ltd | Manufacturing | 2019 |
| Malcomson Brothers Limited | Information & communication | 2024 |
| Mallory Investments Ltd | Real estate | 2019 |
| Manchester Recruitment Agency Limited | Administrative & support | 2011 |
| Mandlovhu Limited | Real estate | 2019 |
| Mandy Medic Kent Limited | Health & social care | 2024 |
| Mango Capital Investments Limited | Financial services | 2024 |
| Manley Westbrook LLP | | 2007 |
| Manna Consultancy Limited | Real estate | 2017 |
| Mannath Properties Ltd | Real estate | 2017 |
| Manor Developments (Kent) Limited | Construction | 2017 |
| Maraya Technologies Limited | Information & communication | 2026 |
| Marchant Guttering Building Specialists Ltd | Construction | 2019 |
| Marchants Services Ltd | Administrative & support | 2022 |
| Marco Rodino Agency Limited | Information & communication | 2017 |
| Marco Rodino Holdings Limited | Real estate | 2023 |
| Marina Barnett Consultancy Limited | Administrative & support | 2025 |