| Lilywhite Properties Ltd | Real estate | 2022 |
| Limbrey Consulting Limited | Professional & scientific | 2023 |
| Lime Components Limited | Manufacturing | 2015 |
| Linear Partners Limited | Administrative & support | 2014 |
| Linksre LLP | | 2026 |
| Lion Learners East Anglia Ltd | Arts & recreation | 2018 |
| Liquid Euphoria Limited | Hospitality | 2025 |
| Liteoptics Limited | Other services | 2006 |
| Little Bird PR Limited | Professional & scientific | 2014 |
| Little Cafe Ltd | Hospitality | 2026 |
| Little Walden Dogbarber Limited | Other services | 2017 |
| Liviva Limited | Administrative & support | 2020 |
| LJB Events Group Limited | Hospitality | 2021 |
| LK Talent Solutions Ltd | Administrative & support | 2024 |
| LLJ578 Limited | Real estate | 2016 |
| LMB Kitchens Limited | Construction | 2020 |
| Lmrt Design Limited | Professional & scientific | 2011 |
| LO Marketing Limited | Professional & scientific | 2016 |
| LO Roche Financial Ltd | Professional & scientific | 2026 |
| Lobster and Bear Developments Limited | Construction | 2019 |
| Local Field Company Ltd | Real estate | 2024 |
| Local Publications (Saffron Walden) Limited | Other services | 1993 |
| Lock Stock & Barrell (Security Services) Limited | Wholesale & retail | 1997 |
| Locksport LLP | | 2024 |
| Loerie Properties Limited | Real estate | 2024 |
| Lofts Hall Farm and Stud LLP | | 2024 |
| Logan Build Limited | Construction | 2006 |
| Lola Nash Capital Ltd | Professional & scientific | 2026 |
| London and Cambridge Pony Parties Ltd | Arts & recreation | 2017 |
| London and Marlborough Group Ltd | Real estate | 2017 |
| London Fashion Exchange Ltd | Wholesale & retail | 2018 |
| London Fields East Side Limited | Real estate | 2017 |
| London Provincial Property Developments Limited | Administrative & support | 2018 |
| Long White Cloud Books Ltd | Information & communication | 2024 |
| Longbeach Estates Limited | Construction | 2012 |
| Longbeach Investments Limited | Real estate | 2015 |
| Longstanton (Golf) Holdings Limited | Real estate | 1999 |
| Longstowe Property Services Limited | Professional & scientific | 2013 |
| Longview Data Systems Ltd | Information & communication | 2013 |
| Loomwork-Ai Ltd | Wholesale & retail | 2026 |
| Lorcan Consulting Limited | Information & communication | 2023 |
| LOU Hansell Ltd | Wholesale & retail | 2022 |
| Louden Group Limited | Professional & scientific | 2018 |
| Lovelycoats Painting & Decorating Ltd | Construction | 2023 |
| Loving Paws Limited | Administrative & support | 2023 |
| Lower Basset Down PV Limited | Energy | 2014 |
| Loxfield Developments Limited | Construction | 1992 |
| LPA Group PLC | Financial services | 1961 |
| LPA Industries Limited | Manufacturing | 1959 |
| LPA Industries Pension Trustees Limited | Financial services | 1978 |
| LPN Scaffolding Ltd | Construction | 2025 |
| LSG Consultancy Limited | Extraterritorial | 2017 |
| LT Ltd | Extraterritorial | 2009 |
| Luachan Ltd | Professional & scientific | 2025 |
| Lucie Dutton Design Ltd | Professional & scientific | 2024 |
| Lucy Davidson Limited | Professional & scientific | 2015 |
| Ludgate Hill Services Ltd | Administrative & support | 2022 |
| Ludlow Search Limited | Administrative & support | 2017 |
| Luft Mvhr Limited | Wholesale & retail | 2017 |
| Lukedmillwardphysiotherapy Ltd | Other services | 2014 |
| Lume Building Solutions Ltd | Construction | 2016 |
| Lumity Collective Ltd | Professional & scientific | 2026 |
| LUX Fashion House Ltd | Wholesale & retail | 2023 |
| Luxury Voyages Limited | Transport & logistics | 2024 |
| Lvbel Nine Ltd | Wholesale & retail | 2025 |
| LWH Management Company Limited | Households | 1994 |
| LX4 Limited | Real estate | 2022 |
| Lysander Limited | Manufacturing | 2024 |
| LZT Contractors Limited | Construction | 2002 |
| M & J Painters & Decorators Ltd | Construction | 2006 |
| M G Electrical Services (Lincs) Limited | Construction | 2008 |
| M M Domestic Energy Limited | Professional & scientific | 2008 |
| M W Building Solutions Ltd | Construction | 2022 |
| M W Suppliers Limited | Wholesale & retail | 2008 |
| M.A.P. Electrical Systems Limited | Construction | 1998 |
| MAC Roofing and Insulation Limited | Construction | 2026 |
| Macdonald Medical Ltd | Health & social care | 2025 |
| Macheme Limited | Information & communication | 2025 |
| Macintosh Property Investments Ltd | Real estate | 2026 |
| Macintyre Art Advisory Limited | Wholesale & retail | 2007 |
| Maddox Real Estate Limited | Real estate | 2018 |
| Made Creative UK Ltd | Professional & scientific | 2024 |
| Madelu Ltd | Health & social care | 2015 |
| Madly Bar’S Ltd | Hospitality | 2019 |
| Magpie Stories Limited | Arts & recreation | 2022 |
| Makuti Tour Ltd | Administrative & support | 2024 |
| Malahide Road Self Storage Centre Limited | Real estate | 2014 |
| Maltings (S.W.) Management Company Limited(The) | Households | 1986 |
| Maltwood Hatcheries Ltd | Agriculture & fishing | 2022 |
| Manchester & Edinburgh Property Investment Co Limited | Real estate | 2012 |
| Mandeville Road 1958 Limited | Extraterritorial | 2014 |
| Manhattan Nails Ltd | Other services | 2024 |
| Mankind Interior Ltd | Construction | 2025 |
| Mannin Investments Limited | Professional & scientific | 2011 |
| Manor Drive (Surbiton) Limited | Households | 1986 |
| Marcmoor Limited | Other services | 1977 |
| Marcusalexander Limited | Construction | 2018 |
| Margaret Whiteford Associates Ltd. | Professional & scientific | 1999 |
| Maria Cave Ltd | Arts & recreation | 2024 |
| Marine Tech Solution Ltd | Manufacturing | 2024 |