| Leoch DBS Limited | Wholesale & retail | 2017 |
| Let's Automate Group Limited | Information & communication | 2025 |
| Lever Typewriter Co. Limited | Real estate | 1964 |
| Leverage Hospitality Ltd | Hospitality | 2023 |
| Lewis's Interiors Limited | Wholesale & retail | 2002 |
| Lhobbs Ltd | Construction | 2022 |
| Liberty Belles K9 Ltd | Extraterritorial | 2010 |
| Liberty PR Limited | Professional & scientific | 2017 |
| Life Safety Solutions Limited | Professional & scientific | 2010 |
| Life Skills First AID Training Ltd | Education | 2026 |
| Lilybelle Beauty & Nails Ltd | Other services | 2021 |
| Limavady Property Holdings Limited | Real estate | 2019 |
| Lime Grove Taverns Limited | Professional & scientific | 2024 |
| Limes Farm Estates Ltd | Real estate | 2024 |
| Limes Farm Gaulby Ltd | Real estate | 2014 |
| Lincoln Gardening Ltd | Administrative & support | 2023 |
| Link Optical Limited | Health & social care | 2009 |
| Linlis Housing Services Ltd | Hospitality | 2023 |
| Lion Heart Property Investments Ltd | Real estate | 2019 |
| Lisa Lovett Studios Limited | Arts & recreation | 2023 |
| Lisa's a Star Tutors Ltd | Education | 2025 |
| Little Bear Ventures Limited | Administrative & support | 2025 |
| Little Bowden Manor Management Company Limited | Households | 1987 |
| Little Folks Limited | Administrative & support | 2003 |
| Little Ladybirds Childcare Ltd | Health & social care | 2020 |
| Little ME Nurseries Limited | Education | 2000 |
| Little Totham Ltd | Transport & logistics | 2021 |
| Liv-It Marketing Ltd | Professional & scientific | 2026 |
| Live Labels Ltd | Wholesale & retail | 2014 |
| Livealife Limited | Construction | 2018 |
| Livelogic Limited | Information & communication | 2013 |
| Livingstone Electrical Services Ltd | Construction | 2024 |
| Livioklein Ltd | Administrative & support | 2024 |
| Lizzie Kinal Ltd | Arts & recreation | 2016 |
| LJS Critical Infrastructure Services Ltd | Administrative & support | 2025 |
| Lloyd Harden Design Limited | Professional & scientific | 2020 |
| LMG Electrical Solutions Ltd | Construction | 2025 |
| LNH Property Ltd | Real estate | 2024 |
| Lockbolt (ERS) Holdings Ltd | Financial services | 2023 |
| Lockbolt (ERS) Ltd | Wholesale & retail | 2010 |
| Locum-Aesthetics by Sophia Ltd | Health & social care | 2015 |
| Loke & Wong Cardiology Limited | Health & social care | 2022 |
| Lombez Corporation Limited | Information & communication | 1992 |
| London's Life Coach Ltd | Health & social care | 2021 |
| Lonestar Assets Limited | Financial services | 2020 |
| Longevia Healthcare Limited | Health & social care | 2024 |
| Longland Safety Management Limited | Professional & scientific | 1998 |
| Longmynd Capital Limited | Professional & scientific | 2014 |
| Longshanks Advisory Limited | Professional & scientific | 2022 |
| Longwood Lane Housing Ltd | Construction | 2025 |
| Lottprop Limited | Administrative & support | 2015 |
| Lough's Kitchen Limited | Wholesale & retail | 2025 |
| Loughton Town Football Club Limited | Arts & recreation | 2014 |
| Loughton Town Y Limited | Arts & recreation | 2024 |
| Louise Blackwell Properties Limited | Real estate | 2021 |
| Love & Mellon Ltd | Real estate | 2023 |
| LOW Carbon Box Limited | Professional & scientific | 2009 |
| LPJ Homes Ltd | Real estate | 2022 |
| LRM Creative Limited | Information & communication | 2009 |
| Lucero Properties LLP | | 2021 |
| Lucy Macdonald Make UP Artist Ltd | Other services | 2013 |
| Luis Palau Evangelistic Team(The) | Other services | 1982 |
| Luke James Digital Ltd | Professional & scientific | 2020 |
| Lula Boutique Limited | Wholesale & retail | 2009 |
| Lumara Wellness Ltd | Health & social care | 2006 |
| Lune Studio Ltd | Information & communication | 2025 |
| Luxury Lifestyle Property Ltd | Real estate | 2017 |
| LW Investment Properties Ltd | Financial services | 2018 |
| LXV Investments Ltd | Construction | 2023 |
| Lynsterubber Limited | Extraterritorial | 2021 |
| Lyon Chase Limited | Professional & scientific | 2017 |
| LZ Automated Limited | Administrative & support | 2024 |
| M & P C Retail Limited | Wholesale & retail | 2015 |
| M & S Groundworks Limited | Construction | 2010 |
| M C Casswell & Sons Company Ltd | Real estate | 2019 |
| M H Glazing Supplies Ltd | Extraterritorial | 2017 |
| M K Essentials Ltd | Wholesale & retail | 2015 |
| M K Property Ltd | Real estate | 2017 |
| M Page Building Contractor Limited | Construction | 2003 |
| M&Gb Support Services Ltd | Other services | 2026 |
| M.G.D.Consultant Limited | Professional & scientific | 2023 |
| M.M.Y. Accountancy Services Limited | Professional & scientific | 1996 |
| M0TZX Publications Ltd | Information & communication | 2019 |
| MA Precision Ltd | Manufacturing | 2013 |
| MAC Carpentry and Joinery Limited | Manufacturing | 2023 |
| MAC Carpentry and Joinery Services Ltd | Manufacturing | 2021 |
| Machine Techniques (UK) Ltd | Manufacturing | 2012 |
| Macsholdings Limited | Hospitality | 2024 |
| Madera Solutions Limited | Other services | 2020 |
| Madison and Fifth Limited | Wholesale & retail | 2024 |
| Magamoor Limited | Wholesale & retail | 2009 |
| Magna Blair Limited | Wholesale & retail | 2016 |
| Magnetiq Leadership Ltd | Professional & scientific | 2022 |
| Magson Maguire Consulting Limited | Professional & scientific | 2004 |
| Maillot Jaune Limited | Real estate | 2024 |
| Main Sparks Limited | Wholesale & retail | 2014 |
| Majos Holdings Limited | Administrative & support | 2021 |
| Mako-Mc Limited | Professional & scientific | 2012 |
| Malachite Associates Limited | Professional & scientific | 2013 |
| Mallorca Batteries (UK) Limited | Wholesale & retail | 2016 |