| Ku'Dah Holdings Ltd | Real estate | 2018 |
| Kumdal Limited | Professional & scientific | 2019 |
| Kupeli Ltd | Real estate | 2026 |
| KVK Tech Europe Limited | Professional & scientific | 2018 |
| Kyrens Barbers Ltd | Other services | 2026 |
| Kyros Technologies Limited | Information & communication | 2026 |
| L & H Building Solutions Limited | Construction | 2020 |
| L & T Packaging & Cleaning Ltd | Administrative & support | 2023 |
| L & T Removals Ltd | Transport & logistics | 2015 |
| L C H Management Ltd | Real estate | 2018 |
| L R Carpentry and General Building Ltd | Construction | 2017 |
| L R Nash (SMK) Ltd | Wholesale & retail | 2016 |
| L Super 007 Limited | Hospitality | 2015 |
| L&M Management Services Limited | Financial services | 2016 |
| L&N Property Group Limited | Real estate | 2025 |
| L&Q Hill Brentford LLP | | 2022 |
| L.E. Property Management Limited | Manufacturing | 2002 |
| LA Barca Cafe Ltd | Hospitality | 2025 |
| LA Gosport Limited | Hospitality | 2024 |
| LA Lupa Limited | Hospitality | 2025 |
| LA Osteria Bar Ltd | Hospitality | 2022 |
| LA Pizza TW Ltd | Hospitality | 2025 |
| LA Scalla Group Ltd | Wholesale & retail | 2020 |
| Laburnum Close Management Company Limited | Professional & scientific | 2004 |
| Ladysmith Associates Ltd | Professional & scientific | 2012 |
| Ladysmith Capital Ltd | Real estate | 2019 |
| Lake Card Store Ltd | Wholesale & retail | 2024 |
| Lala Building Services Ltd | Construction | 2024 |
| Lamb Legacy Capital Ltd | Financial services | 2026 |
| Landmark Window Co. Ltd | Construction | 2003 |
| Langfield Electrical Ltd | Construction | 2024 |
| Lanni Loves Ltd | Wholesale & retail | 2017 |
| Lantern Demolition & Grab Hire Limited | Administrative & support | 2015 |
| Larsen House Management Company Limited | Households | 2021 |
| Last Minute Fair Ride Limited | Arts & recreation | 2023 |
| Latifa Properties Ltd | Real estate | 2023 |
| Latimer Hill (Hardwick) LLP | | 2019 |
| Latimer Hill Attleborough LLP | | 2021 |
| Latimer Hill Compass Park LLP | | 2025 |
| Latimer Hill LLP | | 2017 |
| Latinos Weston UK Ltd | Hospitality | 2025 |
| Laulbaul Limited | Wholesale & retail | 2021 |
| Laurie Walk Cafe Limited | Hospitality | 2024 |
| Lavender Close Developments Ltd | Construction | 2020 |
| Law Services Ltd. | Construction | 2021 |
| LAX Holdings Ltd | Real estate | 2021 |
| Layberry Ltd | Hospitality | 2013 |
| Layken Ltd | Other services | 2022 |
| LCI Solutions Limited | Construction | 2019 |
| LCT & Daughters UK Ltd | Transport & logistics | 2019 |
| LDJ New Homes Limited | Real estate | 2019 |
| LDN Recovery Services Limited | Wholesale & retail | 2024 |
| Ldnherts Ltd | Professional & scientific | 2026 |
| LE Petit Paris Limited | Professional & scientific | 2019 |
| LE Software MAN Limited | Information & communication | 1985 |
| LEA Bridge Express Ltd | Wholesale & retail | 2018 |
| LEA Bridge Hill LLP | | 2014 |
| LEA Road Properties Limited | Professional & scientific | 2016 |
| LEA Valley Drainage Services Ltd | Administrative & support | 2017 |
| LEA Valley Motor Company (Nazeing) Limited | Wholesale & retail | 1987 |
| Leading Black Women Ltd. | Professional & scientific | 2024 |
| Learning Talking Limited | Education | 2012 |
| Lease Vehicle Solutions Limited | Administrative & support | 1998 |
| Leboela Holdings Ltd | Real estate | 2025 |
| LEE Valley Consulting Limited | Professional & scientific | 2017 |
| LEE WOR Flooring Limited | Construction | 2017 |
| Lee-Moon Design Ltd | Professional & scientific | 2017 |
| Lee-Moon Property Ltd | Real estate | 2025 |
| Leeu Capital Limited | Professional & scientific | 2020 |
| Legacy Growth Partners Ltd | Professional & scientific | 2025 |
| Leivetts Limited | Real estate | 2022 |
| Lena's World Ltd | Other services | 2026 |
| LEO Boxing & Management Ltd | Administrative & support | 2018 |
| Leomakes Consulting Limited | Professional & scientific | 2020 |
| Leonard F Jollye (Holdings) Limited | Financial services | 2005 |
| Leonard F. Jollye Limited | Professional & scientific | 1996 |
| Leonard F.Jollye (Brookmans Park) Limited | Wholesale & retail | 1971 |
| Lewis Berger International Supplies Limited | Wholesale & retail | 1993 |
| Lewis Watkins Design Ltd | Professional & scientific | 2014 |
| Lexen Construction Ltd | Construction | 2024 |
| Leygate Properties Ltd | Construction | 2025 |
| LH Publishing Ltd | Information & communication | 2018 |
| LHT Logistics Limited | Transport & logistics | 2001 |
| LHT Production Limited | Construction | 2017 |
| LHT Warehousing and Distribution Limited | Transport & logistics | 2022 |
| Liam Contractors Ltd | Construction | 2026 |
| Lifestyle Homes by Carter Remy Ltd | Real estate | 2022 |
| Lina 1999 Ltd | Hospitality | 2022 |
| Linnaeus Herbals Limited | Information & communication | 2017 |
| Linsell Stores Ltd | Wholesale & retail | 2004 |
| Linton Road (Great Abington) Management Company Limited | Households | 2019 |
| Linxify Limited | Wholesale & retail | 2024 |
| Lion City (UK) Limited | Wholesale & retail | 2013 |
| Lion Mobile Chef Ltd | Hospitality | 2020 |
| Lisles Incorporated Limited | Information & communication | 2023 |
| Liteswitch TV Limited | Information & communication | 2012 |
| Little Chalfont Estate Management Company Limited | Households | 2025 |
| Little Chunk Trading Ltd | Wholesale & retail | 2023 |
| Little Face Rigging Ltd | Construction | 2019 |
| Little Nest Supplies Ltd | Wholesale & retail | 2026 |