| LJS Civils & Services Ltd | Construction | 2023 |
| LLL Properties Ltd | Real estate | 2021 |
| Lloyads Limited | Administrative & support | 2017 |
| LMC Cars Ltd | Wholesale & retail | 2012 |
| Lmiva Ltd | Administrative & support | 2023 |
| Lmjr Ltd | Arts & recreation | 2017 |
| Lnoh Ltd | Transport & logistics | 2017 |
| Lock Doctor Essex Limited | Manufacturing | 2022 |
| Lockies Fitness & Lifestyle Limited | Wholesale & retail | 2024 |
| Lofty Houses Limited | Real estate | 2021 |
| London Fields Bottega Ltd | Other services | 2025 |
| London Garden Rooms Ltd | Extraterritorial | 2013 |
| London Glass and Balustrades Limited | Construction | 2021 |
| London Martin Services Ltd | Professional & scientific | 2019 |
| London Prime Produce Ltd | Hospitality | 2012 |
| London Stansted Cargo Limited | Transport & logistics | 2004 |
| London Vintage BUS Hire Ltd | Administrative & support | 2016 |
| Londonexecminibuses.Com Limited | Transport & logistics | 2017 |
| Londonmagicstore UK Limited | Wholesale & retail | 2014 |
| Longfield Advisors Limited | Professional & scientific | 2025 |
| LOO Hire Ltd | Water & waste | 2018 |
| Lord of Spice Ltd | Hospitality | 2025 |
| Lordcom Limited | Other services | 2025 |
| Lordship Lane Property Ltd | Real estate | 2024 |
| Lottie & Ollie Limited | Administrative & support | 2011 |
| Lottie Capital Limited | Real estate | 2025 |
| LP Restoration Essex Ltd | Construction | 2025 |
| LPA1 Consulting Limited | Administrative & support | 2013 |
| LS Decs Limited | Construction | 2018 |
| LS Financial Services Limited | Administrative & support | 2019 |
| LTS UK Building & Landscaping Ltd | Construction | 2025 |
| Lucha Films Ltd | Information & communication | 2020 |
| Lucona Venture Limited | Transport & logistics | 2014 |
| Lucy Burchell Yoga Limited | Education | 2024 |
| Luden Automotive Limited | Wholesale & retail | 2016 |
| Lulu Rose Ltd | Wholesale & retail | 2024 |
| Lumi Beci Brand Ltd | Manufacturing | 2023 |
| Lundgren Limited | Professional & scientific | 2014 |
| Luxe Cabinetry Ltd | Extraterritorial | 2020 |
| Luxe Chelsea Living Ltd | Wholesale & retail | 2025 |
| Luxe Hair Bar Ltd | Other services | 2023 |
| Luxe Refurbs Group Ltd | Construction | 2026 |
| Luxe Skin Aesthetics UK Limited | Other services | 2021 |
| Luxmipur Samity UK Limited | Other services | 2023 |
| Lymo Rides Group Ltd | Transport & logistics | 2025 |
| L’Amour Beauty Upminster Ltd | Other services | 2023 |
| L’Amour by Claudia Crow Ltd | Wholesale & retail | 2026 |
| M & a Carpentry (UK) Ltd | Construction | 2005 |
| M & a Facilities Ltd | Construction | 2015 |
| M Mayes Limited | Manufacturing | 2013 |
| M R Properties Limited | Real estate | 2013 |
| M&M Solutions Ltd | Information & communication | 2010 |
| M&O Test Management Limited | Professional & scientific | 2022 |
| M&V Trading Ltd | Hospitality | 2012 |
| M.A.D.E Corporation Ltd | Arts & recreation | 2021 |
| M.A.S. Developments (London) Ltd | Construction | 2025 |
| M.A.S. Developments Limited | Construction | 2016 |
| M.B.F.M. Limited | Construction | 2007 |
| M1 Plastering Ltd | Construction | 2022 |
| MA Football Analysis Ltd | Professional & scientific | 2017 |
| MAA Family Ltd | Wholesale & retail | 2014 |
| MAA World Ltd | Administrative & support | 2020 |
| Macesons Ltd | Wholesale & retail | 2023 |
| Maddison Roofing Ltd | Construction | 2023 |
| Maddox & KAN Ltd | Hospitality | 2024 |
| Madel Homes Ltd | Real estate | 2022 |
| Madel Properties LLP | | 2013 |
| Maesbury Estates Limited | Real estate | 1999 |
| MAG Mechanical Services Ltd | Construction | 2019 |
| Magic Nails and Beauty Ltd | Other services | 2024 |
| Magic Razor Ltd | Other services | 2023 |
| Maib Ltd | Real estate | 2020 |
| Main Family Holdings Limited | Real estate | 2025 |
| Mainhood Ltd | Education | 2024 |
| Mairs Carbon Services Limited | Financial services | 2024 |
| Major Group Developments Limited | Real estate | 2018 |
| Make IT OUR Holmes Limited | Real estate | 2025 |
| Manage My Courses Limited | Information & communication | 2023 |
| Mango Marketing & Media Ltd | Real estate | 2010 |
| Manic Blondes Ltd | Information & communication | 2015 |
| Manorbrooke Limited | Other services | 2025 |
| Manorfield (UK) Ltd | Construction | 2010 |
| Maple Real Estate Limited | Construction | 2021 |
| Maplin Energy Limited | Professional & scientific | 2022 |
| Maplin Engineering Limited | Professional & scientific | 2014 |
| Maplin Studio Limited | Professional & scientific | 2022 |
| Mark Kennedy & Co Ltd | Professional & scientific | 2005 |
| Mark Two Controls & Electrical Services Ltd | Manufacturing | 2013 |
| Marketing Under Construction Ltd | Professional & scientific | 2025 |
| Marlborough Real Estate Properties Ltd | Real estate | 2020 |
| Marpasc Ltd | Construction | 2011 |
| Marsh Made Construction Ltd | Construction | 2011 |
| Marston Moretaine Property Holdings Limited | Transport & logistics | 2014 |
| Martin Edwards Consulting Limited | Financial services | 2013 |
| Marway Financial Planning Limited | Professional & scientific | 2021 |
| Masala Grill Original Ltd | Hospitality | 2009 |
| Masons Installations Heating Plumbing Services Limited | Construction | 2016 |
| Master Excavation Ltd | Construction | 2022 |
| Match 2 Box Ltd | Arts & recreation | 2021 |
| Matthew Joseph Consultancy Ltd | Public administration | 2015 |