| Lavender Hill Garage Enfield Limited | Energy | 2006 |
| Lawrence Galkoff Associates Limited | Information & communication | 1997 |
| Lawrence Rockey | | 1998 |
| LBA Insight Limited | Professional & scientific | 2004 |
| LBQ Physio Limited | Health & social care | 2014 |
| Leadertec Limited | Wholesale & retail | 2000 |
| Leafi International Limited | Hospitality | 2018 |
| Leafi Limited | Hospitality | 2006 |
| Leagrave Property Co.Limited | Real estate | 1963 |
| Leap to Success Limited | Real estate | 2019 |
| Learn 2 Learn Limited | Professional & scientific | 2003 |
| Ledger Accountancy Ltd | Professional & scientific | 1999 |
| LEE Auto Services Limited | Wholesale & retail | 2004 |
| LEE. Tait | | 1998 |
| Leebank Builders Limited | | 1989 |
| Leemark Engineering (Hayes) Limited | Manufacturing | 1966 |
| Leepfrog Systems Limited | Information & communication | 1995 |
| Legacybuildco Ltd | Construction | 2024 |
| Legal Information Limited | Professional & scientific | 2001 |
| Legend (UK) Limited | | 1986 |
| Leprosy Mission Corporation(The) | Health & social care | 1934 |
| LES Thompson and Company Limited | Construction | 2003 |
| Let's Print (Finchley) Limited | Wholesale & retail | 2003 |
| Lets Party Entertainments Limited | Arts & recreation | 2001 |
| Lewes Close Limited | Households | 2004 |
| Lexstorer Holding Ltd | Financial services | 2025 |
| LGC Creations Ltd | Real estate | 2025 |
| LHR Building Control Services Limited | Administrative & support | 1997 |
| Liam Properties Mill Hill Ltd | Real estate | 2024 |
| Libra Contract Services Ltd. | | 1996 |
| Lieberman Gallery Limited | Wholesale & retail | 2005 |
| Life Style Developments and Construction Limited | Arts & recreation | 1993 |
| Lift-Wand Space Solutions Limited | Real estate | 2017 |
| LIK Shot Recordings Ltd | Information & communication | 2006 |
| Limpet Productions Limited | Professional & scientific | 2003 |
| Link Solution Limited | Administrative & support | 2000 |
| Linus Investments Limited | Financial services | 2015 |
| Linus Nasrak Limited | Information & communication | 2006 |
| Lion Studios Limited T/A Lion Creative Limited | Professional & scientific | 1980 |
| Liquid Media Limited | Information & communication | 2000 |
| Lithographic Supplies and Equipment Company Limited | Manufacturing | 1985 |
| Little Kiran Productions Limited | Information & communication | 2003 |
| Liveup Properties Limited | Real estate | 2024 |
| Living Entertainment Limited | Wholesale & retail | 2002 |
| Lizard MAN Studio Ltd. | Information & communication | 2008 |
| Ljdc Services Limited | Real estate | 1987 |
| Lloshi Estate Group Ltd | Real estate | 2025 |
| Lloyd Insight Solutions Ltd | Financial services | 2023 |
| LMB25 Ltd | Hospitality | 2025 |
| Lmcs Limited | Health & social care | 2007 |
| LMH Retail Limited | Wholesale & retail | 2003 |
| LNC Group Limited | Construction | 2019 |
| Lockwood Telecoms Ltd | Information & communication | 2024 |
| Loft Space Limited | Construction | 1993 |
| Logicom Communications Limited | Manufacturing | 1984 |
| Logicweb Ltd | Information & communication | 1998 |
| Logix Limited | Information & communication | 1994 |
| Lola Productions Limited | Information & communication | 2013 |
| London & Home Counties Safes Ltd | Administrative & support | 1995 |
| London & International Ltd | Professional & scientific | 2003 |
| London & Oxford Investments Limited | Construction | 2002 |
| London Art Workshop Limited | Professional & scientific | 2006 |
| London Bible College Limited | Extraterritorial | 2003 |
| London Building & Construction Company Limited | Construction | 2002 |
| London College of Accountancy Limited | Extraterritorial | 2015 |
| London Contractors Ltd | Real estate | 2003 |
| London Financial & Management Services Limited | Professional & scientific | 1991 |
| London Inn Hotels (Stratford) Limited | Hospitality | 2001 |
| London Land Securities Limited | Real estate | 1983 |
| London Mainland Limited | Hospitality | 1997 |
| London Money Market Limited | Information & communication | 1999 |
| London Obesity Surgery Ltd | Health & social care | 2005 |
| London School of Theology | Education | 1943 |
| London Seeds International Limited | Wholesale & retail | 2005 |
| London Sound Limited | Other services | 2003 |
| London Stock Market Limited | Professional & scientific | 1999 |
| London Tamil Centre | Health & social care | 1993 |
| London Textile Solutions Limited | Wholesale & retail | 2023 |
| London Therapy With Amita Ltd | Health & social care | 2015 |
| London World Finance Ltd | Administrative & support | 2005 |
| London's Voice Ltd | Transport & logistics | 2019 |
| Londspel Investments Limited | Real estate | 1958 |
| Longfield Properties Limited | Administrative & support | 2007 |
| Longreach Property Limited | Real estate | 2021 |
| Longview Drive Limited | Arts & recreation | 2009 |
| Lotara Management Ltd | Administrative & support | 2008 |
| Lotus Flower Holdings Limited | Professional & scientific | 2013 |
| Lotus Nest Limited | Real estate | 2025 |
| Lotus Property Services Ltd | Real estate | 2006 |
| Louis O'Regan Limited | Transport & logistics | 2003 |
| Louis Properties Ltd | Real estate | 2002 |
| Lovesportuk Limited | Arts & recreation | 2006 |
| Lower Road Signs Ltd | Manufacturing | 2007 |
| LPC Limited | Professional & scientific | 1988 |
| LPR Solutions Limited | Information & communication | 2004 |
| LPT 4 Limited | Professional & scientific | 2005 |
| LT. Walters | | 1998 |
| Lubricants UK Limited | Manufacturing | 1908 |
| Ludipuss Ltd. | Manufacturing | 2016 |
| Lukes & Jukes Estates Limited | Other services | 2007 |