| London in Hand Ltd | Wholesale & retail | 2025 |
| London Metropolitan College Limited | Education | 2012 |
| London River Limited | Education | 2019 |
| London Skyline Ltd | Transport & logistics | 2023 |
| Londongate Publishing Limited | Information & communication | 2019 |
| Long Island House Ltd | Real estate | 2019 |
| Long Lane Wines Limited | Wholesale & retail | 2021 |
| Loong Enterprises Ltd | Information & communication | 2014 |
| Loong Properties Ltd | Real estate | 2016 |
| Loopia AI Ltd | Information & communication | 2020 |
| Lords UK Trading Ltd | Wholesale & retail | 2021 |
| Lotus Nail Salon Limited | Other services | 2026 |
| Lough Conn Castle Limited | Hospitality | 2022 |
| Lough Conn Holdings Limited | Real estate | 2022 |
| Lough Conn Services Limited | Hospitality | 2022 |
| Lrformworks Ltd | Construction | 2019 |
| LTI Technology Solutions Limited | Information & communication | 2015 |
| LTI UK Purchaser Ltd. | Financial services | 2026 |
| Lublinianie Ltd | Information & communication | 2015 |
| Luftavia Holdings Limited | Real estate | 2017 |
| Luftavia Ltd | Manufacturing | 2015 |
| Luftavia Technical Training Ltd | Education | 2023 |
| Luke Scott Stunts Ltd | Information & communication | 2014 |
| Luly Consulting Ltd | Information & communication | 2022 |
| Lumina Technology Limited | Professional & scientific | 2013 |
| Lupercal Systems Limited | Administrative & support | 2024 |
| Lurox Limited | Manufacturing | 2025 |
| Lusso LA Casa Ltd | Wholesale & retail | 2026 |
| Luther Systems Limited | Information & communication | 2015 |
| Lutman Properties and Management Ltd | Real estate | 2024 |
| Luxborough Maintenance Services Limited | Construction | 2022 |
| Luxe Amira Limited | Wholesale & retail | 2025 |
| Luxe Chauffeuring Ltd | Transport & logistics | 2023 |
| Luxe Wheels Chauffeurs Ltd | Transport & logistics | 2025 |
| Luxury Honeymoon Limited | Hospitality | 2025 |
| Lydia Britton Ltd | Professional & scientific | 2015 |
| Lyst Consulting Partnership Ltd | Information & communication | 2022 |
| L’Atelier Charlene.T London Ltd | Manufacturing | 2023 |
| M & M Patel Property Limited | Real estate | 2026 |
| M Ahsn Limited | Wholesale & retail | 2026 |
| M Congreve Services Ltd | Administrative & support | 2016 |
| M Faulkner Builder Ltd | Construction | 2011 |
| M Hussain Properties Limited | Real estate | 2024 |
| M J Environmental Services Limited | Professional & scientific | 2007 |
| M RAY Vision Ltd | Transport & logistics | 2024 |
| M&A Corp Ltd | Construction | 2021 |
| M&D Ortho Ltd | Health & social care | 2023 |
| M&S Food and Wine Limited | Wholesale & retail | 2013 |
| M&V Holdings Limited | Financial services | 2025 |
| M.Mustaqim and Sons Food Ltd | Administrative & support | 2019 |
| M.Oblueteam Ltd | Professional & scientific | 2026 |
| M.T.D.Limited | Transport & logistics | 1941 |
| MAA Durga Limited | Hospitality | 2012 |
| Maagar UK Limited | Wholesale & retail | 1999 |
| Maaintech Limited | Wholesale & retail | 2010 |
| Maala Property Services Ltd | Real estate | 2017 |
| Maan Road Limited | Transport & logistics | 2025 |
| Maanav Limited | Real estate | 2021 |
| MAC O'Brien Consulting Ltd | Professional & scientific | 2025 |
| Macovei Solution Ltd | Transport & logistics | 2025 |
| Macspare Limited | Other services | 2018 |
| MAD Frank Ltd | Wholesale & retail | 2019 |
| Madualaiz INT Ltd | Real estate | 2021 |
| Madyn Limited | Health & social care | 2015 |
| Mafeco Electrical Services Ltd | Construction | 2024 |
| Maganda MEH Limited | Health & social care | 2023 |
| Magic Cleaning Ltd | Administrative & support | 2019 |
| Magna Cartaa Limited | Hospitality | 2024 |
| Magnetik IT Ltd | Information & communication | 2025 |
| Magniflow Limited | Information & communication | 2025 |
| Magnolia View Managment Limited | Extraterritorial | 2014 |
| Magnum Land and Homes Ltd | Construction | 2020 |
| Mahal Trucking Ltd | Transport & logistics | 2015 |
| Mahi Capital Limited | Information & communication | 2024 |
| Maid in Brazil Cleaning Services Limited | Administrative & support | 2014 |
| Mail Resource Logistics Limited | Transport & logistics | 2024 |
| Majenta BOW Limited | Administrative & support | 2022 |
| Majestic Project Solutions Ltd | Construction | 2023 |
| Majestic UK Homes Limited | Real estate | 2023 |
| Majestik Aesthetics Limited | Other services | 2022 |
| Majhail Builders 06 Ltd | Construction | 2026 |
| Makki Management Limited | Administrative & support | 2018 |
| Maktek IT Ltd | Information & communication | 2025 |
| Mall & Sons Limited | Administrative & support | 2014 |
| Malo Support Ltd | Education | 2025 |
| Malta Topco Limited | Information & communication | 2016 |
| Manage Estate & Investment Ltd | Real estate | 2023 |
| Managed AI Systems Ltd | Information & communication | 2026 |
| Manes Construction Ltd | Construction | 2025 |
| Manga Originals Ltd | Wholesale & retail | 2024 |
| Manhattan Esquire Ltd | Construction | 2025 |
| Maninderpal Ltd | Real estate | 2025 |
| Mann UK Flow Control Company Ltd | Wholesale & retail | 2022 |
| Manocta Limited | Real estate | 2026 |
| Manor Court Management Company (Egham) Limited | Households | 2006 |
| Many Drops Ltd | Wholesale & retail | 2017 |
| Maple Court (Surbiton) Management Ltd | Households | 2007 |
| Maple Montessori Ltd | Education | 2025 |
| Maple ROW Ltd | Wholesale & retail | 2024 |
| Maprin Limited | Administrative & support | 2021 |