| L Burridge Ltd | Administrative & support | 2010 |
| L K Business Services Limited | Administrative & support | 2012 |
| L K Pike Ltd | Health & social care | 2019 |
| L Miller Properties Limited | Real estate | 2020 |
| L Tindell Electrical Limited | Construction | 2024 |
| L&Gigi Ltd | Construction | 2025 |
| L&M Planning Services Ltd | Construction | 2026 |
| L&M Planning Solutions Ltd | Construction | 2022 |
| L&M Railway Solutions Ltd | Administrative & support | 2026 |
| L.B.C. & J. Courts Residents' Association Limited | Households | 1984 |
| L.H Roof Services Ltd | Construction | 2024 |
| L.H Scaffolding & Co Ltd | Construction | 2024 |
| LA Provence (Camden) Limited | Professional & scientific | 2019 |
| LA Talent Ltd | Professional & scientific | 2024 |
| Lab-Salon Limited | Other services | 2016 |
| Label Print Services Limited | Manufacturing | 2005 |
| Laboratory for Geospatial Solutions Ltd | Information & communication | 2025 |
| Laburnum Court (Crystal Palace) Ltd | Households | 2019 |
| Lady Elizabeth Limited | Professional & scientific | 2020 |
| Lagd Limited | Construction | 2019 |
| Lagos African Church Grammar School Old Student Association. UK Ltd | Other services | 2018 |
| Lakedale Coffee Limited | Hospitality | 2018 |
| Lakedale Group Limited | Professional & scientific | 1988 |
| Lakka Investments Limited | Real estate | 2015 |
| Lakka Services Limited | Real estate | 2020 |
| LALA1 Ltd | Hospitality | 2022 |
| Lale Catering Ltd | Hospitality | 2024 |
| Lambarts Limited | Wholesale & retail | 1981 |
| Lanasuperfine Ltd | Other services | 2018 |
| Land & Water Estates Limited | Professional & scientific | 2000 |
| Land & Water Services Ltd | Professional & scientific | 1992 |
| Land & Water Special Projects Limited | Construction | 2003 |
| Land and Water Group Limited | Professional & scientific | 2002 |
| Landlord Compliant Services Limited | Real estate | 2025 |
| Lane & Frankham Limited | Construction | 2013 |
| Lang Dwellings Ltd | Real estate | 2024 |
| Lang Taxi Service Limited | Transport & logistics | 2015 |
| Langdon Holdings Ltd | Real estate | 2019 |
| Langdon Homes Limited | Real estate | 2019 |
| Langiappe Productions Limited | Information & communication | 2013 |
| Langson Integra Limited | Real estate | 2020 |
| Languages OUT There Limited | Administrative & support | 2005 |
| Lanz.London Limited | Information & communication | 2026 |
| Laptronic Systems Limited | Wholesale & retail | 2012 |
| Laptronics Group Limited | Wholesale & retail | 2023 |
| Laptronics Limited | Wholesale & retail | 2013 |
| Lark in the Park (Community Projects) | Other services | 2006 |
| Lark Tech Services Ltd | Information & communication | 2017 |
| Lasenby Estates Ltd | Real estate | 2025 |
| Lash ME UPX Ltd | Other services | 2024 |
| Lashbrook Cabinet Making Limited | Manufacturing | 2020 |
| Last Branch Ltd | Construction | 2023 |
| Last Outpost Limited | Hospitality | 2019 |
| Laswell Limited | Real estate | 1989 |
| Latchbrook Property & Estate Maintenance Services Limited | Real estate | 1999 |
| Latchmore Court (Hitchin) Limited | Extraterritorial | 2017 |
| Latham Lift Services Limited | Manufacturing | 2024 |
| Laura Melhuish Ltd | Administrative & support | 2023 |
| Laurelwood Group Limited | Wholesale & retail | 2023 |
| Laurence Residential Limited | Professional & scientific | 2017 |
| Lavant Property Ltd | Real estate | 2021 |
| Lavelle Consultancy Limited | Administrative & support | 2020 |
| Lawguide Limited | Information & communication | 1995 |
| Lawrence Court (Sidcup) Management Company Limited | Households | 2011 |
| Lawrence Haulage Limited | Administrative & support | 2015 |
| Lawrie Park 39 Limited | Administrative & support | 2009 |
| Lawrie Park Developments Limited | Real estate | 2000 |
| Lb&Co Inventory Ltd | Real estate | 2025 |
| LB4 Control System Limited | Construction | 2023 |
| LBC Plumbing & Heating Services Ltd | Construction | 2005 |
| LBC Subsea Cable Services Limited | Administrative & support | 2018 |
| LBD Systems Limited | Construction | 2026 |
| LC Surveyors Ltd | Professional & scientific | 2019 |
| LCB Homes Ltd | Real estate | 2019 |
| Lclc Learning & Support Community Interest Company | Administrative & support | 2025 |
| Lclc Romford Ltd | Education | 2019 |
| Lclc Tuition Ltd | Education | 2022 |
| LD Decorators Ltd | Construction | 2019 |
| LD Services Ltd | Construction | 2015 |
| LDN Roofing Solutions Limited | Construction | 2019 |
| Leading Edge Services Limited | Professional & scientific | 2025 |
| Leads Tutorials Ltd | Education | 2016 |
| Leah Morgan Coaching & Consultancy Limited | Education | 2017 |
| Leasing Direct Limited | Real estate | 1995 |
| Leds Contractors Limited | Professional & scientific | 2019 |
| LEE Air Conditioning Services Limited | Administrative & support | 1979 |
| LEE Loeffler Limited | Professional & scientific | 2013 |
| LEE R Services Limited | Construction | 2024 |
| LEE Terrace Homes Limited | Real estate | 2020 |
| Leemma Limited | Administrative & support | 2025 |
| Lefa Enterprises Limited | Professional & scientific | 1991 |
| Lefa Investments Ltd | Financial services | 2021 |
| Lefa Property Ltd | Construction | 2013 |
| Lefa Residential Ltd | Real estate | 2019 |
| Legacy Professionals Limited | Professional & scientific | 2020 |
| Legends of Eltham - Bar & Grill Ltd | Hospitality | 2023 |
| Lenco Property Maintenance Ltd | Construction | 2017 |
| Lenny Holdings Limited | Real estate | 2024 |
| Lensara UK Ltd | Wholesale & retail | 2026 |
| LEO Bidco Limited | Financial services | 2025 |