| LDH Building (Walthams) Limited | Construction | 2014 |
| LDH Lettings Limited | Real estate | 2022 |
| LDI Inspection Services Limited | Other services | 2014 |
| LDL Lettings Ltd | Real estate | 2023 |
| Ldlc Services Limited | Construction | 2025 |
| Ldot Digital Studios Ltd | Information & communication | 2020 |
| Ldprop Ltd | Real estate | 2025 |
| LDS Brickwork Ltd | Construction | 2014 |
| LDS Fitness Ltd | Health & social care | 2025 |
| LE BON Avion Limited | Transport & logistics | 2004 |
| LE Continent Limited | Wholesale & retail | 2026 |
| LE Feuvre Media Ltd | Wholesale & retail | 2011 |
| Lead Chameleon Ltd | Information & communication | 2022 |
| Lead Recon Ltd | Real estate | 2021 |
| Leading Agencies Limited | | 1987 |
| Leading Edge Builders Ltd | Construction | 2016 |
| Leading for Results Limited | Professional & scientific | 2014 |
| Leading Leadwork Services Limited | Construction | 2000 |
| Leading Ledgers Ltd | Professional & scientific | 2011 |
| Leading Locations Limited | Administrative & support | 2009 |
| Leads Every Day Limited | Professional & scientific | 2013 |
| LEADS2CUSTOMERS Ltd | Information & communication | 2024 |
| Leadstone Holdings Limited | Financial services | 2017 |
| Leadstore Ltd | Information & communication | 2008 |
| Leadway Support Services Ltd | Hospitality | 2020 |
| Leaf & Lodge Ltd | Wholesale & retail | 2025 |
| Leaf & Sparkle Cleaning Ltd | Hospitality | 2024 |
| Leafy Productions Limited | Information & communication | 2018 |
| Leah Mair Digital Solutions Limited | Professional & scientific | 2025 |
| Leamington Films Limited | Information & communication | 2025 |
| Lean Facilitation Limited | Professional & scientific | 2011 |
| Lean Fit (Southampton) Ltd | Arts & recreation | 2023 |
| Lean Sigma Projects Ltd | Professional & scientific | 2008 |
| Lean SIX Sigma Resolutions Ltd. | Professional & scientific | 2014 |
| Leander Consulting Limited | Information & communication | 2001 |
| Leanne Court Management Ltd | Households | 2021 |
| Leap Build Ltd | Construction | 2025 |
| Leap Frog Ceramics Warfield Ltd | Wholesale & retail | 2012 |
| LEAP4 Ltd | Professional & scientific | 2012 |
| Learn the Ropes Ltd | Education | 2025 |
| Learnoffice Ltd | Information & communication | 2025 |
| Leather Luxe Design Limited | Manufacturing | 2017 |
| Leaver Property Ltd | Real estate | 2017 |
| Leavers to Leaders Ltd | Education | 2019 |
| Lebek DRY Lining Ltd | Construction | 2014 |
| Lecie Ltd | Wholesale & retail | 2021 |
| Lecouto Ltd | Wholesale & retail | 2021 |
| Ledas Property Maintenance Ltd | Construction | 2026 |
| Ledaz Lighting Limited | Wholesale & retail | 2016 |
| Ledgera Limited | Professional & scientific | 2025 |
| LEE Button Associates Limited | Professional & scientific | 2025 |
| LEE Court Mansions Management Co Limited | Households | 1982 |
| LEE Denham IT Consulting Ltd | Information & communication | 2019 |
| LEE Grant Sheeran Ltd | Wholesale & retail | 2023 |
| LEE Hayward Ltd | Construction | 2007 |
| LEE Home 34 Ltd | Hospitality | 2021 |
| LEE Malyon Plumbing & Heating Ltd | Construction | 2024 |
| LEE Ross Property Group Ltd | Real estate | 2021 |
| Lee's Trade Tyres Limited | Wholesale & retail | 2020 |
| Leedham Marine Consultants Limited | Transport & logistics | 1995 |
| Leeo Transport Limited | Transport & logistics | 2025 |
| Leepeck International Limited | Extraterritorial | 2007 |
| Leese Brickwork Limited | Construction | 2018 |
| Leeward Amity Ltd | Hospitality | 2024 |
| Leeway Developments Ltd | Real estate | 2021 |
| Leewinzy Limited | Administrative & support | 2024 |
| Left Lane Studio Ltd | Professional & scientific | 2025 |
| Leftfield Charters Limited | Transport & logistics | 2024 |
| Legacy Building Projects Ltd | Construction | 2025 |
| Legacy Construction Southern Ltd | Construction | 2026 |
| Legacy Group Southern Ltd | Financial services | 2026 |
| Legacy Homes Southern Ltd | Construction | 2026 |
| Legacy of Leather Ltd | Manufacturing | 2024 |
| Legacy Roots Group Ltd | Hospitality | 2025 |
| Legacy Southern Ltd | Construction | 2026 |
| Legacy Wheels Car Deliveries Ltd | Transport & logistics | 2026 |
| Legafin Consulting Limited | Professional & scientific | 2026 |
| Legal & Management Services Limited | Construction | 2003 |
| Legal Compliance and Safety Services Ltd | Information & communication | 2007 |
| Legal Compliance Solutions LLP | | 2024 |
| Legendri UK Limited | Financial services | 2018 |
| Legends Healthcare Ltd | Administrative & support | 2023 |
| Legero Limited | Wholesale & retail | 2018 |
| Leggett's Transport Limited | Information & communication | 1961 |
| Legis Solutions Limited | Information & communication | 2006 |
| Legit Inc Ltd | Wholesale & retail | 2023 |
| Leicester Street Limited | Real estate | 2002 |
| Leicester William Gill Limited | Professional & scientific | 2022 |
| Leigh Court (Southampton) Ltd | Other services | 2013 |
| Leigham Hall (Block One) RTM Company Limited | Households | 2020 |
| Leigham Hall (Block Two) RTM Company Limited | Households | 2020 |
| Leighton Homes Ltd | Real estate | 2013 |
| Leighton Projects Limited | Real estate | 2013 |
| Leisha Norman Interior Designs Ltd | Professional & scientific | 2024 |
| Leisure Television Rights Limited | Arts & recreation | 2021 |
| Lekker Ltd | Professional & scientific | 2025 |
| Lemax Ltd | Transport & logistics | 2015 |
| Lemon Difficult Ltd | Hospitality | 2023 |
| Lemon Lumba Limited | Construction | 2021 |
| Lemon Trace Limited | Information & communication | 2022 |