| Lammas (Ealing) Limited | Real estate | 2024 |
| Lammin Property Management Ltd | Real estate | 2024 |
| Lampern Renewables Ltd | Construction | 2021 |
| Lamtorobinta Limited | Health & social care | 2015 |
| Lancaster London Holdings Limited | Real estate | 2018 |
| Lance Lotts Ltd | Arts & recreation | 2019 |
| Land Management Group Limited | Real estate | 1914 |
| Land Marketing Limited | Administrative & support | 2019 |
| Landas Group Limited | Real estate | 2018 |
| Landers & Associates (Building & Design) Limited | Professional & scientific | 1988 |
| Landers & Associates Limited | Extraterritorial | 1991 |
| Landlord Certificate London Limited | Other services | 2022 |
| Landmark Living Developers Construction Limited | Construction | 2023 |
| Landmark Living Developers Limited | Real estate | 2023 |
| Landmore Contractors Ltd | Construction | 2024 |
| Landmore Holdings Ltd | Financial services | 2024 |
| Landmore Homes Limited | Construction | 2022 |
| Langrose Property Investments Limited | Construction | 1984 |
| Langston Road Estates Limited | Construction | 2019 |
| Langton Gate (Hornchurch) Management Limited | Households | 1998 |
| Lanrak Limited | Professional & scientific | 2018 |
| Lansbury Properties Ltd | Real estate | 2022 |
| Lantern Path HR Consulting Ltd | Administrative & support | 2026 |
| LAO Nova Ltd | Construction | 2022 |
| Lapa Construction Ltd | Construction | 2019 |
| Lapcress Ltd | Health & social care | 2022 |
| Laptop Disposal Limited | Information & communication | 2025 |
| Lara T Limited | Financial services | 2013 |
| Larabayo Medical Limited | Health & social care | 2014 |
| Larachi Ltd | Wholesale & retail | 2022 |
| Larchwood Maintenance Limited | Construction | 2017 |
| Larkins M&E Services Limited | Professional & scientific | 2014 |
| LAROSHSINCE1995 Ltd | Wholesale & retail | 2024 |
| Larr Properties Ltd | Real estate | 2024 |
| Laryoons Real Estate Limited | Construction | 2011 |
| LAS Aguas Ltd | Education | 2024 |
| Lascaratos Consulting Ltd | Health & social care | 2018 |
| Lascaratos Ltd | Real estate | 2023 |
| Lascenko Holdings Ltd | Financial services | 2026 |
| Laser Essex Limited | Construction | 1996 |
| Laser Eyes Limited | Real estate | 2021 |
| Laser Mayhem Limited | Arts & recreation | 2005 |
| Laserloaf Ltd | Information & communication | 2017 |
| Lash Lift Limited | Wholesale & retail | 2025 |
| Lash Shack Academy Ltd | Other services | 2025 |
| Lashaw Limited | Real estate | 2022 |
| Lashi Build Ltd | Construction | 2021 |
| Lasn Ltd | Real estate | 2018 |
| Last Chapter Films Ltd | Arts & recreation | 2024 |
| Lastingham Haulage Ltd | Transport & logistics | 2014 |
| Later Life Audio and Radio Co-Operative Community Interest Company | Information & communication | 2025 |
| Lattice Consulting Ltd | Information & communication | 2013 |
| Lattice Cubes Limited | Information & communication | 2009 |
| Laur MLS Decorating Ltd | Construction | 2026 |
| Laura Developments Limited | Real estate | 2013 |
| Laurence Ellis Studio Limited | Professional & scientific | 2017 |
| Laurenzo Ltd | Construction | 2025 |
| Lauta 1926 Ltd | Transport & logistics | 2014 |
| Lavan KRD Ltd | Wholesale & retail | 2025 |
| Lavanto Ltd | Wholesale & retail | 2016 |
| Lavender Mill Management Company Limited | Households | 2026 |
| Lavish Wash Ltd | Wholesale & retail | 2019 |
| Law Office of Richard Henry - Legal Consultant Advocate and Mediation Services Ltd | Professional & scientific | 2021 |
| Lawful Links Ltd | Information & communication | 2024 |
| Lawson Golf Limited | Arts & recreation | 2024 |
| Laxmi Group Ltd | Real estate | 2019 |
| Laxmi Limited | Real estate | 1984 |
| Laxmiji Property Limited | Real estate | 2019 |
| Laxton Projects Limited | Construction | 2025 |
| Laxton Property Investments Limited | Households | 2022 |
| Layinks Solutions Ltd | Administrative & support | 2023 |
| Layright Ltd | Construction | 2016 |
| Laytec Flooring Limited | Construction | 2019 |
| Layyza Logistics Ltd | Transport & logistics | 2025 |
| Lazaroiu Ovidiu Ltd | Construction | 2021 |
| Lazure Worldwide UK Ltd | Wholesale & retail | 2023 |
| LB Cartech Limited | Wholesale & retail | 2024 |
| LB Construction Solutions Limited | Construction | 2015 |
| LBA Holdings Ltd | Real estate | 2024 |
| LBB Roofing Ltd | Construction | 2024 |
| LBI Management Limited | Professional & scientific | 2016 |
| LBR Financial Solutions Limited | Financial services | 2013 |
| LBR Holdings Limited | Real estate | 2008 |
| LBT Consulting Limited | Professional & scientific | 2015 |
| LC Mechanical Ltd | Construction | 2020 |
| Lc&T Property Solutions Ltd | Arts & recreation | 2018 |
| LCM Drones Ltd | Information & communication | 2026 |
| LCM Homes Ltd | Real estate | 2019 |
| Lcmedsec Limited | Administrative & support | 2025 |
| LD Accounting Ltd | Professional & scientific | 2016 |
| LD Dang Medical Limited | Health & social care | 2023 |
| Lddpro Limited | Construction | 2019 |
| LDL & ROB Group Limited | Construction | 2021 |
| LDM Management Limited | Households | 2022 |
| LDM Operations Ltd | Construction | 2026 |
| LDN Shuttle Limited | Transport & logistics | 2025 |
| LE Grandoria Ltd | Wholesale & retail | 2025 |
| Le-Art Contractors Ltd | Construction | 2023 |
| Leacroft Services Limited | Hospitality | 2000 |
| Leadcroft Limited | | 1993 |