| LCN Capital Partners (London) Limited | Real estate | 2015 |
| Lcuk Milton Keynes Ltd | Other services | 2021 |
| LD Hair Professional Ltd | Other services | 2025 |
| LD Timeless Aesthetics Ltd | Extraterritorial | 2023 |
| LD2U Ltd | Information & communication | 2019 |
| LDH Drive Limited | Transport & logistics | 2020 |
| Ldrm Construction Ltd | Construction | 2022 |
| LDS Maintenance Ltd | Manufacturing | 2015 |
| LDS Supply Ltd | Manufacturing | 2018 |
| LDT Electrical Limited | Construction | 2024 |
| LE Blanc Developments Ltd | Other services | 2019 |
| LE Chateau Clothing Limited | Wholesale & retail | 2004 |
| LE Village Enterprises Ltd | Hospitality | 2025 |
| Lead FLY Limited | Information & communication | 2020 |
| Lead Pro Solutions Ltd | Professional & scientific | 2024 |
| Leader Business Experts Ltd | Professional & scientific | 2022 |
| Leaders in Care Limited | Health & social care | 2022 |
| Leadership by Inspiration Limited | Professional & scientific | 2017 |
| Leadership Skills Foundation | Education | 2023 |
| Leadership Success Holdings Limited | Professional & scientific | 2018 |
| Leadership Success Operations Limited | Professional & scientific | 2018 |
| Leadexq Limited | Real estate | 2025 |
| Leading and Contemporary Music Limited | Other services | 1983 |
| Leaf Adventures Ltd | Professional & scientific | 2021 |
| Leafblow Limited | Extraterritorial | 2022 |
| Leaford Limited | Administrative & support | 2009 |
| Leah Heal Limited | Administrative & support | 2012 |
| Leamington Road Estate Management Company (Luton) Limited | Real estate | 1984 |
| Lean Vision Consultancy Ltd. | Professional & scientific | 2015 |
| Learners Connect Limited | Education | 2021 |
| Learners HQ Ltd | Information & communication | 2023 |
| Learnhydrogen Ltd | Manufacturing | 2025 |
| Learning Academy Private Limited | Professional & scientific | 2006 |
| Learning Productions Ltd | Information & communication | 2021 |
| Leather Working Group | Other services | 2012 |
| Leaves and Roots Limited | Education | 2021 |
| Leca & J Marketing Limited | Professional & scientific | 2024 |
| Leca Marketing Limited | Professional & scientific | 2024 |
| Lecm Industries Ltd | Transport & logistics | 2019 |
| Leco Rail Ltd | Construction | 2026 |
| Lecta Limited | Administrative & support | 2020 |
| Lecta Paper UK Limited | Wholesale & retail | 1985 |
| Lecta Self-Adhesives UK Limited | Wholesale & retail | 2025 |
| Lecton House Management Company Limited | Households | 2016 |
| LED Bulb World Limited | Wholesale & retail | 2014 |
| Leda Entertainment Ltd | Information & communication | 2014 |
| Ledboxframe Limited | Manufacturing | 2022 |
| Ledgerlyapp Ltd | Information & communication | 2025 |
| Ledgers Accountancy Limited | Professional & scientific | 1994 |
| Ledgers Secretaries Limited | Professional & scientific | 2000 |
| Ledgr Accountants Ltd | Professional & scientific | 2025 |
| Ledster the Mechanic Limited | Wholesale & retail | 2012 |
| Leduweglobal Ltd | Wholesale & retail | 2023 |
| LEE & Sons Carpentry & Building Services Limited | Construction | 2020 |
| LEE Ceilings and Partitions Ltd | Construction | 2020 |
| LEE Charlotte and Bright Healthcare Ltd | Health & social care | 2015 |
| LEE Consulting Limited | Professional & scientific | 2007 |
| LEE Perry Productions Limited | Arts & recreation | 2002 |
| LEE PM Services Ltd | Administrative & support | 2021 |
| Lee&Son 88 Ltd | Hospitality | 2022 |
| Lee's Care Services Ltd | Health & social care | 2021 |
| Lee's Catering Services Ltd | Hospitality | 2024 |
| Lee's Sandwiches Ltd | Hospitality | 2024 |
| Leed Consulting Limited | Professional & scientific | 2016 |
| Leed Resources PLC | Financial services | 2006 |
| Leeders Hardware Limited | Wholesale & retail | 2009 |
| Leelin Ltd | Hospitality | 2014 |
| Leemoll Services Limited | Construction | 2000 |
| Leetech Ltd | Information & communication | 2025 |
| Leevon International Recruitment Ltd | Administrative & support | 2019 |
| Leficia Healthcare Services Ltd | Public administration | 2026 |
| Legacia Ltd | Real estate | 2022 |
| Legacy Accounts Ltd | Professional & scientific | 2013 |
| Legacy Capital Group Ltd | Real estate | 2026 |
| Legacy Protection Limited | Professional & scientific | 2016 |
| Legacybuilding@Logistics Ltd | Construction | 2024 |
| Legacyhall Limited | Real estate | 2020 |
| Legal Graph Company Limited | Information & communication | 2019 |
| Legal Sector Solutions Ltd | Financial services | 2019 |
| Legend Group Holdings (UK) Limited | Financial services | 2025 |
| Legend One Ltd | Hospitality | 2019 |
| Legend One Sushi Limited | Hospitality | 2024 |
| Legendary Transport Ltd | Transport & logistics | 2026 |
| Legion Transport UK Ltd | Transport & logistics | 2018 |
| Legionella Testing Limited | Water & waste | 2012 |
| Leica Geosystems Limited | Wholesale & retail | 1964 |
| Leighton Aerials Limited | Administrative & support | 2009 |
| Leighton Buzzard Property Ltd | Real estate | 2017 |
| Leighton Buzzard Sports Association Limited | Education | 1927 |
| Leighton Industrial Park Management Limited | Real estate | 1991 |
| Leighton Landscaping Limited | Administrative & support | 2004 |
| Leighton Venture Limited | Real estate | 2024 |
| Leila's Beauty Salon Ltd | Other services | 2020 |
| Leira Accessories Ltd | Wholesale & retail | 2023 |
| Leisure Services Management Limited | Arts & recreation | 2016 |
| Lemaju Trans Ltd | Transport & logistics | 2023 |
| Lemar Auto Motors Limited | Wholesale & retail | 2024 |
| Lemma Logistics Limited | Transport & logistics | 2025 |
| Lemon Moose Limited | Professional & scientific | 2005 |
| Lemongrass Media Ltd | Information & communication | 2013 |