| Ljpa Ltd | Administrative & support | 2026 |
| LJT Creatives Ltd | Arts & recreation | 2023 |
| LM Blasting Ltd | Construction | 2025 |
| LM Fittings Limited | Construction | 2022 |
| LM UK Aviation Limited | Administrative & support | 2001 |
| LMB Group Enterprises Ltd | Financial services | 2025 |
| LMB Group Investments Ltd | Professional & scientific | 2025 |
| LMD Properties Ltd | Real estate | 2014 |
| LMV Fitness Ltd | Health & social care | 2020 |
| Lockerlink Ltd | Extraterritorial | 2023 |
| Lockfit Bishop's Stortford Ltd | Administrative & support | 2024 |
| Lockresq Ltd | Other services | 2020 |
| LOCKS4LESS Locksmiths Limited | Administrative & support | 2019 |
| Lockwood Environment Limited | Professional & scientific | 2014 |
| Lockyers Limited | Information & communication | 2014 |
| LOG Private Ltd | Real estate | 2014 |
| LOG Property Ltd | Real estate | 2020 |
| Logos BIO Company Ltd | Wholesale & retail | 2016 |
| Loli and Robi Ltd | Hospitality | 2026 |
| Lollybob Limited | Financial services | 2025 |
| LON REC Limited | Administrative & support | 2024 |
| London Avengers CC Limited | Arts & recreation | 2024 |
| London City Consulting Services Limited | Professional & scientific | 2015 |
| London Drylining & Facades Ltd | Construction | 2019 |
| London Electrical Maintenance Ltd | Manufacturing | 2021 |
| London Keys Car Hire Ltd | Administrative & support | 2025 |
| London Lebanese Suppliers Ltd | Extraterritorial | 2013 |
| London Luxury Transport Limited | Transport & logistics | 2019 |
| London Road Industrial Units Management Company Limited | Households | 1988 |
| Londons Flowers Ltd | Wholesale & retail | 2025 |
| Longevitee Ltd | Information & communication | 2025 |
| Longfield Motor Co. Ltd | Wholesale & retail | 2006 |
| Look Photogenic Limited | Wholesale & retail | 2024 |
| Lost Heart Ltd | Information & communication | 2020 |
| Lottica Property Development Ltd | Construction | 2024 |
| Loughton Commercial Cleaners Ltd | Other services | 2018 |
| Loughton Tyres Mustafa Limited | Wholesale & retail | 2026 |
| Louis Austin Limited | Information & communication | 2021 |
| Louise Roach Limited | Arts & recreation | 2011 |
| Love Talya Academy Ltd | Education | 2022 |
| Lovely Hall Limited | Real estate | 2017 |
| Lovesweetslife Ltd | Wholesale & retail | 2022 |
| LSE Security Limited | Construction | 2014 |
| LSH Mortgages Limited | Financial services | 2008 |
| LTC Services Limited | Real estate | 2023 |
| Ltd Engineering Ltd | Professional & scientific | 2011 |
| LTG Hertford Limited | Professional & scientific | 2013 |
| Lucavi Ltd | Wholesale & retail | 2021 |
| Lucerna Works Ltd | Information & communication | 2026 |
| Lucette Issartel Psychotherapist Ltd | Professional & scientific | 2004 |
| Luciaferrato Ltd | Professional & scientific | 2025 |
| Ludaga Ltd | Transport & logistics | 2017 |
| Luke Rolls Ltd | Professional & scientific | 2023 |
| Lukes Jukes Ltd | Arts & recreation | 2026 |
| Lumae Audio Ltd | Information & communication | 2025 |
| Lumira Studio Limited | Information & communication | 2023 |
| Lumolab Ltd | Manufacturing | 2025 |
| Lunabare Ltd | Wholesale & retail | 2020 |
| Lunar Luxuries Ltd | Professional & scientific | 2023 |
| Lusaian Ltd | Wholesale & retail | 2026 |
| Lush Trade & Transport Ltd | Transport & logistics | 2020 |
| Luther Electronics Ltd | Manufacturing | 2025 |
| LUX Jets Limited | Administrative & support | 2022 |
| Luxe Residential Services Ltd | Water & waste | 2025 |
| Luxury Construction Group Ltd | Construction | 2022 |
| LV Electrical Solutions Ltd | Construction | 2017 |
| LVG Plumbing &Heating Ltd | Construction | 2011 |
| Lynx Builders Ltd | Construction | 2025 |
| Lyons and Brown Ltd | Construction | 2017 |
| M & D Developments (Horringer) Limited | Households | 2003 |
| M & R Properties (Essex) Limited | Real estate | 1990 |
| M a Hill HR Consultancy Ltd | Professional & scientific | 2021 |
| M Cowley Services Limited | Professional & scientific | 2026 |
| M E K Solutions Limited | Administrative & support | 2015 |
| M Phillips Consultants Ltd | Information & communication | 2007 |
| M This & That Ltd | Construction | 2026 |
| M&A Education Services Ltd | Education | 2026 |
| M&A Ventures Ltd | Health & social care | 2022 |
| M&D Developers Limited | Construction | 2019 |
| M&O Coffee Ltd | Hospitality | 2024 |
| M.G.M. Property Holdings (Liverpool) Limited | Construction | 1973 |
| M.P.C. Procurement & Consultancy Limited | Transport & logistics | 2015 |
| MAB Property Developments Limited | Real estate | 2017 |
| Macame Limited | Professional & scientific | 2024 |
| Macfie Property Investments Ltd | Real estate | 2019 |
| Macnab Property Rentals Ltd | Real estate | 2023 |
| Macronote Ltd | Information & communication | 2025 |
| MAD Sparks Ltd | Manufacturing | 2022 |
| Made With Fuel Limited | Information & communication | 2016 |
| Magalhaes Consultancy Ltd | Administrative & support | 2023 |
| Magic BAG Ltd | Professional & scientific | 2002 |
| Magic of Foresters Events Limited | Other services | 2019 |
| Magical Design & Internet Ltd | Information & communication | 2026 |
| Maison Atlas Ltd | Real estate | 2022 |
| Maison Madison Limited | Other services | 2026 |
| Maitland Close Management Company Ltd | Households | 2018 |
| Maiv Ltd | Information & communication | 2024 |
| Make Waves Digital Ltd | Professional & scientific | 2024 |
| Makeup by Georgia Limited | Other services | 2022 |
| Mako Developments (Battle) Limited | Construction | 2022 |