| Lockmills Ltd | Other services | 2019 |
| Lockwell Limited | Manufacturing | 1989 |
| Lockwise Limited | Construction | 1991 |
| Logos Unlimited Limited | Manufacturing | 2013 |
| Lois Solution Ltd | Administrative & support | 2025 |
| Lollo Rosso Italia Ltd | Hospitality | 2015 |
| London and Geneva Property Limited | Extraterritorial | 2013 |
| London North East Residential Limited | Real estate | 2026 |
| Lone Wolf Developments NE Ltd | Real estate | 2021 |
| Long Green Pigs Limited | Agriculture & fishing | 2020 |
| Long Stride Entertainment Ltd | Information & communication | 2022 |
| Longrigg 1965 Limited | Extraterritorial | 2014 |
| Longshore Drift Limited | Real estate | 2022 |
| Lonsdale Financial Ltd | Professional & scientific | 2014 |
| Looking Glass Training Ltd | Education | 2015 |
| Lookout Lounge Limited | Hospitality | 2023 |
| Lord Technical (Holdco) Limited | Construction | 2012 |
| Lostbox Ltd | Information & communication | 2012 |
| Louie (Holdings) Limited | Professional & scientific | 2007 |
| Louie Properties Limited | Real estate | 2008 |
| Louietex Ltd | Wholesale & retail | 2008 |
| Louise Potts Wills and Probate Limited | Professional & scientific | 2021 |
| Loujax Properties Limited | Real estate | 2019 |
| Love OUR Tiny Blue DOT Limited | Wholesale & retail | 2018 |
| LOW Fell Barber Ltd | Other services | 2025 |
| LOW Fell Community Pre-School C.I.C. | Education | 2019 |
| LOW Fell Design Studios Limited | | 1986 |
| LOW Fell Environmental Consultancy Services Ltd | Professional & scientific | 2017 |
| LOW Fell Florists Ltd | Wholesale & retail | 2023 |
| LOW Fell Hospitality Ltd | Hospitality | 2026 |
| LOW Fell Monsun Restaurant Ltd | Hospitality | 2018 |
| LOW Fell Mortgage Services Ltd | Financial services | 2011 |
| LOW Fell Physio Ltd. | Health & social care | 2015 |
| LOW Fell Psychological Services Limited | Health & social care | 2015 |
| LOW Mount Farm Ltd | Agriculture & fishing | 2024 |
| LOW Warden Barns 1 Ltd | Hospitality | 2012 |
| Lower Lodge Candles Limited | Wholesale & retail | 2011 |
| Lowfell African Produce Limited | Wholesale & retail | 2021 |
| Lowfell Leisure Ltd | Hospitality | 2018 |
| Lowfell Properties Limited | Real estate | 2003 |
| Lozach Holdings Ltd | Financial services | 2025 |
| Lpadgett Ltd. | Health & social care | 2023 |
| LS4U Ltd | Administrative & support | 2025 |
| LSA Anaesthetics Ltd | Health & social care | 2020 |
| LST Consultancy Ltd | Professional & scientific | 2024 |
| LT Flooring Solutions Ltd | Construction | 2023 |
| Luan Craftsman Co Limited | Construction | 2024 |
| Lubrication Systems Limited | Professional & scientific | 2010 |
| Lucca Pizza Company Ltd | Hospitality | 2022 |
| Luchy Ltd | Real estate | 2021 |
| Lucid Signs Limited | Extraterritorial | 1996 |
| Lucion Civils Limited | Professional & scientific | 2018 |
| Lucion Consulting Limited | Administrative & support | 2007 |
| Lucion Environmental Limited | Extraterritorial | 2022 |
| Lucion Limited | Professional & scientific | 2008 |
| Lucion Survey (Landform) Ltd | Professional & scientific | 2000 |
| Ludgate 373 Limited | Construction | 2006 |
| Lugano Developments Limited | Real estate | 2007 |
| Lugano Management Limited | Real estate | 2026 |
| Lugano Montagu Limited | Real estate | 2017 |
| Luke Huitson Ltd. | Information & communication | 2015 |
| Luma Solar Solutions Ltd | Construction | 2026 |
| Luna Properties (NE) Ltd | Real estate | 2025 |
| Lunapat Property Ltd | Real estate | 2025 |
| Lunato Properties Ltd | Real estate | 2025 |
| Lupton House Limited | Real estate | 2017 |
| Lusso Concierge and Housekeeping Ltd | Administrative & support | 2020 |
| LUV TAN UK Limited | Other services | 2022 |
| Luvlets Commercial Ltd | Real estate | 2025 |
| Luvlets Ltd | Real estate | 2018 |
| LUX and Living Estates Ltd | Real estate | 2023 |
| Luxdon Limited | Other services | 2018 |
| Luxe Domes Ltd | Hospitality | 2021 |
| Luxury Depot Ltd | Wholesale & retail | 2026 |
| Luxury Leisure | Arts & recreation | 1989 |
| Lvxport Ltd | Wholesale & retail | 2019 |
| LWA Property Maintenance Limited | Construction | 2007 |
| Lyfedigit Ltd | Information & communication | 2025 |
| Lymphoma Consulting Limited | Health & social care | 2026 |
| Lyncroft Finance Limited | Professional & scientific | 2013 |
| Lyndengate Management Limited | Real estate | 1991 |
| Lyndhurst Bowling Club (1905) Limited | Arts & recreation | 2019 |
| Lyndhurst Early Years Limited | Education | 2013 |
| Lyndsey Morton Ltd | Other services | 2019 |
| Lynked Advisors LLP | | 2023 |
| Lynked Limited | Financial services | 2008 |
| LZJ Electrics Ltd | Construction | 2026 |
| M & K Courier Services Ltd | Transport & logistics | 2019 |
| M & R FM Ltd | Financial services | 2012 |
| M a Todd Ltd | Manufacturing | 2026 |
| M and N Heating Engineering Limited | Construction | 2025 |
| M Branco Ltd | Health & social care | 2015 |
| M E Electrical (North East) Limited | Construction | 2017 |
| M Hoey Civils Ltd | Construction | 2025 |
| M Mansoor Ltd | Health & social care | 2014 |
| M Popa Ltd | Health & social care | 2014 |
| M R M Cable Group Limited | Financial services | 2026 |
| M R M Cables Limited | Construction | 2017 |
| M R M Sports Limited | Hospitality | 2023 |
| M S Davison Limited | Professional & scientific | 2013 |