| LT Prestige Ltd | Transport & logistics | 2025 |
| LT Tutoring Ltd | Education | 2026 |
| LTM Compliance (Milton Keynes) Limited | Water & waste | 2013 |
| LTU Trade Limited | Wholesale & retail | 2025 |
| Lubxng Club Ltd | Health & social care | 2026 |
| Luca Iasi Ltd | Construction | 2024 |
| Luca Services Ltd | Transport & logistics | 2017 |
| Lucas Travel Ltd | Administrative & support | 2025 |
| Lucatranslogistics Ltd | Construction | 2020 |
| Lucia Hair Art Limited | Other services | 2008 |
| Lucian's Garden Care Ltd | Administrative & support | 2026 |
| Lucid Electronics Limited | Wholesale & retail | 2016 |
| Lucid Print Management Ltd | Professional & scientific | 2023 |
| Luckhurst Digital Ltd | Administrative & support | 2019 |
| Lucky 14 Design & Marketing Ltd | Professional & scientific | 2018 |
| Lucky Hare Books Ltd | Wholesale & retail | 2025 |
| Lucrezio Limited | Hospitality | 2020 |
| Lucy Transport Ltd | Transport & logistics | 2022 |
| Lucy Winter Design Ltd | Professional & scientific | 2016 |
| Lugra Solutions Ltd | Real estate | 2025 |
| Luigi Mileti Ltd | Transport & logistics | 2023 |
| Lukasz Klimek Limited | Construction | 2018 |
| Lukasz Palamarz Limited | Wholesale & retail | 2015 |
| Lukrau Auto Ltd | Wholesale & retail | 2019 |
| Luma Community CIC | Health & social care | 2021 |
| Luma Content Ltd | Professional & scientific | 2019 |
| Luma Sounds Ltd | Administrative & support | 2017 |
| Lumak Properties Ltd | Real estate | 2024 |
| LUMEN8 Electrical Ltd | Construction | 2023 |
| Lumi Digital Design Ltd | Professional & scientific | 2021 |
| Lumi HR Ltd | Professional & scientific | 2026 |
| Lumia Online Limited | Real estate | 2020 |
| Lumina Solarworks Ltd | Energy | 2025 |
| Lumini Occasions Limited | Wholesale & retail | 2025 |
| Luminous Reward Consulting Ltd | Professional & scientific | 2017 |
| Luna Love Limited | Real estate | 2025 |
| Luna Supported Living Limited | Health & social care | 2019 |
| Luna WOS Ltd | Real estate | 2022 |
| Lunar Lounge and Academy Ltd | Health & social care | 2025 |
| Lunara Dance Collective Ltd | Arts & recreation | 2026 |
| Lung Health London Ltd | Health & social care | 2025 |
| Lunna Homes Ltd | Real estate | 2023 |
| LUO Social Forum | Administrative & support | 2008 |
| Lurwich Limited | Real estate | 2018 |
| Luthford Grace Investments Ltd | Real estate | 2025 |
| Luthfur Medical Services Ltd | Wholesale & retail | 2024 |
| Luton Kitchens and Bathrooms Ltd | Manufacturing | 2017 |
| LUX Cleaning Services Ltd | Administrative & support | 2026 |
| Luxe Bites Catering and Events Ltd | Wholesale & retail | 2026 |
| Luxe Cleaning and Moving Services Ltd | Transport & logistics | 2026 |
| Luxe Legacy Ltd | Wholesale & retail | 2025 |
| Luxe Nails and Beauty Limited | Other services | 2017 |
| Luxe Photo Booths UK Limited | Other services | 2016 |
| Luxico Ltd | Wholesale & retail | 2021 |
| Luxury Homes Limited | Real estate | 2024 |
| Luxury Lavender Gift Box Company Ltd | Wholesale & retail | 2023 |
| Luxury Wedding Cars Ltd | Transport & logistics | 2024 |
| Luxus Venetian Ltd | Construction | 2024 |
| Lver Limited | Wholesale & retail | 2011 |
| LW Drylining Ltd | Construction | 2022 |
| LW Operations Limited | Information & communication | 2026 |
| LWB Installation and Logistics Limited | Other services | 2017 |
| Lygrove Close (Management Company) Limited | Administrative & support | 2015 |
| Lykos Leisure Limited | Real estate | 2020 |
| Lymer Mortgages Limited | Administrative & support | 2023 |
| Lyndhurst Property Management Limited | Professional & scientific | 2009 |
| Lyndmont Limited | Real estate | 2019 |
| Lynmouth Management Company Limited | Households | 2004 |
| Lyon Court Hitchin Management Limited | Households | 2013 |
| Lzhcleaninggroup Ltd | Administrative & support | 2024 |
| LZR Trans Ltd | Transport & logistics | 2018 |
| M & Co Accountants Limited | Professional & scientific | 2016 |
| M & D H Insurance Services Ltd | Financial services | 2002 |
| M & E Estates Ltd | Real estate | 2025 |
| M & F Building Construction Limited | Construction | 2014 |
| M & I Management Solutions Ltd | Water & waste | 2017 |
| M & J Group (Construction & Roofing) Ltd | Construction | 1978 |
| M & J Mortgages Limited | Financial services | 2006 |
| M & K Pharmachem Limited | Wholesale & retail | 2008 |
| M & M 24/7 Ltd | Administrative & support | 2021 |
| M & M Home Support Ltd | Other services | 2019 |
| M & M International (U.K.) Limited | Professional & scientific | 1990 |
| M & N Furniture Limited | Wholesale & retail | 2007 |
| M & P Supplies Limited | Wholesale & retail | 2009 |
| M & R Transport Northants Ltd | Transport & logistics | 2024 |
| M a Baig Ltd | Public administration | 2023 |
| M a Perkins Itsm Services Ltd | Information & communication | 2025 |
| M a Transport Services Limited | Transport & logistics | 2016 |
| M and E Kababs Limited | Hospitality | 2023 |
| M and E People Limited | Information & communication | 2009 |
| M and S Garden Services Ltd | Other services | 2010 |
| M B Fabrication Ltd | Manufacturing | 2026 |
| M Bates Financial Services Limited | Financial services | 2017 |
| M C Electrical Consultants Limited | Construction | 2017 |
| M Concetta Ltd | Hospitality | 2019 |
| M D Evans Farriery Ltd | Agriculture & fishing | 2021 |
| M Davis Property Maintenance Ltd | Administrative & support | 2007 |
| M Dumpleton Carpentry Ltd | Construction | 2016 |
| M F Hospitality Ltd | Hospitality | 2025 |
| M Gulliver Holdings Limited | Financial services | 2022 |