| Lookfantastic Group Limited | Wholesale & retail | 2005 |
| Lookfantastic London Limited | Other services | 2007 |
| Lookfantastic Salons Limited | Administrative & support | 2007 |
| Lookfantastic.Com.Ltd | Wholesale & retail | 1998 |
| Loopdl Limited | Information & communication | 2025 |
| Looped Marketing Ltd | Professional & scientific | 2025 |
| Lord Hospitality Limited | Hospitality | 2026 |
| Lord Interiors Ltd | Professional & scientific | 2026 |
| Lordgate Estates Limited | Administrative & support | 2017 |
| Lorenz De-Vine Limited | Professional & scientific | 2025 |
| Loreto Education Trust | Education | 2012 |
| Loreto Grammar School | Education | 2012 |
| Lorien Engineering Solutions Limited | Professional & scientific | 1984 |
| Lorimer Foster Services Ltd | Health & social care | 2003 |
| Lorimer Holdings Ltd | Real estate | 2015 |
| Lostock Gardens Management Company Limited | Real estate | 2018 |
| Lotus Direct Ltd | Construction | 2018 |
| Lotus Nexus Limited | Information & communication | 2026 |
| Lotus Orthodontics Limited | Health & social care | 2007 |
| Lotus Plus Ltd | Health & social care | 2017 |
| Loughlin Materials Ltd | Construction | 2018 |
| Louis Henry Limited | Other services | 2017 |
| Love & Co (London) Limited | Professional & scientific | 2007 |
| Love Beauty Salon Ltd | Other services | 2020 |
| Love the Oceans | Agriculture & fishing | 2014 |
| Love the Oceans Conservation | Professional & scientific | 2018 |
| Love What YOU DO Ltd | Administrative & support | 2010 |
| Loveitbookit.Com Ltd | Administrative & support | 2012 |
| Lovely JOB Ltd | Administrative & support | 2025 |
| Lovetree Capital Partners Limited | Financial services | 2022 |
| Lowaa Collective C.I.C. | Arts & recreation | 2025 |
| Lowood Properties Ltd | Administrative & support | 2017 |
| LP North Eighteen Limited | Wholesale & retail | 2023 |
| LP North Fifteen Limited | Wholesale & retail | 2023 |
| LP North Fourteen Limited | Wholesale & retail | 2023 |
| LP North Seventeen Limited | Wholesale & retail | 2023 |
| LP North Sixteen Limited | Wholesale & retail | 2023 |
| LP SD One Hundred Twenty Eight Limited | Wholesale & retail | 2023 |
| LP SD One Hundred Twenty Nine Limited | Wholesale & retail | 2023 |
| LPE Holdco Limited | Financial services | 2020 |
| LPM Landscape Contractor & Supplier Ltd | Other services | 2013 |
| LPM Living Limited | Real estate | 2025 |
| LPP Reserved UK Limited | Wholesale & retail | 2015 |
| LPX Investments Limited | Financial services | 2025 |
| LR712 Limited | Professional & scientific | 2023 |
| LRE 1 Limited | Real estate | 2022 |
| LRE 2 Limited | Real estate | 2023 |
| LRE 3 Buyer Co Limited | Real estate | 2025 |
| LRE 3 Limited | Real estate | 2025 |
| LRE Partnership 1 Limited | Financial services | 2023 |
| LRE Partnership 2 Limited | Financial services | 2023 |
| LRL 2017 Ltd | Financial services | 2017 |
| LRL Future Finance Limited | Financial services | 2020 |
| LS1 Limited | Professional & scientific | 2000 |
| LSQ Claims Ltd | Professional & scientific | 2018 |
| LTH World Travel Limited | Administrative & support | 2023 |
| Ltmfd Limited | Administrative & support | 2013 |
| Ltpic Technology Limited | Information & communication | 2021 |
| LU Management Ltd | Real estate | 2024 |
| Lucas Green Limited | Wholesale & retail | 2008 |
| Lucem Nexus Limited | Administrative & support | 2024 |
| Lucie Jones Limited | Professional & scientific | 2026 |
| Lucille Haire Legal Services Limited | Professional & scientific | 2015 |
| Lucvel Services Limited | Construction | 2022 |
| Lucy Hesford Swim School Limited | Arts & recreation | 2005 |
| Lugo Coffee Limited | Hospitality | 2024 |
| Luke Caratti Limited | Professional & scientific | 2021 |
| Luke Pilkington Industries Limited | Wholesale & retail | 2024 |
| Lukis Technologies Limited | Wholesale & retail | 2024 |
| Luksus Design Group Ltd | Real estate | 2021 |
| Luma Life Ltd | Financial services | 2025 |
| Lumen Interim & Consulting Limited | Professional & scientific | 2025 |
| Lumenpulse Alphaled Limited | Wholesale & retail | 2014 |
| Lumenpulse UK Limited | Wholesale & retail | 2011 |
| Lumicut Ltd | Manufacturing | 2025 |
| Lumin Architects Limited | Professional & scientific | 2019 |
| Luminary Learning Hub Ltd | Education | 2025 |
| Luminous Shadows Ltd | Health & social care | 2018 |
| Lumo Consulting Limited | Administrative & support | 2024 |
| Luna Design and Build Limited | Construction | 2016 |
| Lunar Investments Ltd | Real estate | 2017 |
| Lunbro Capital Limited | Administrative & support | 2020 |
| Lunbro Group Limited | Information & communication | 2018 |
| Lunbro Holiday Homes Limited | Hospitality | 2021 |
| Lunbro Lettings Limited | Real estate | 2025 |
| Lunbro Properties Limited | Real estate | 2019 |
| Lund Aero Tech Limited | Professional & scientific | 2022 |
| Lupa Investment Management UK Ltd | Financial services | 2020 |
| Luxari Travel Ltd | Administrative & support | 2023 |
| Luxe Cheshire Limited | Wholesale & retail | 2021 |
| Luxe Equine Ltd | Other services | 2023 |
| Luxury Land Ltd | Real estate | 2024 |
| Lvpf Holdings Limited | Arts & recreation | 2025 |
| Lwcprop Ltd | Financial services | 2026 |
| Lydall Industrial Filtration (Emea) Limited | Manufacturing | 1970 |
| Lydall Industrial Filtration Textile Manufacturing (Emea) Limited | Manufacturing | 1998 |
| Lydall UK Ltd | Financial services | 2014 |
| Lyme Bay Holidays Limited | Administrative & support | 2002 |
| Lyme Court Management Limited | Households | 2004 |
| Lymm (Villafont) Limited | Construction | 2017 |