| LME Consulting Ltd | Professional & scientific | 2019 |
| LO Trans Ltd | Transport & logistics | 2018 |
| Localcrest Limited | Real estate | 1981 |
| Localground Residents Management Limited | Households | 1987 |
| Locar Limited | Wholesale & retail | 2019 |
| Lochinver House School | Education | 2002 |
| Lock IT in Studio Limited | Professional & scientific | 2024 |
| Lockenfeld Limited | Financial services | 2015 |
| Logix IT Recruitment Limited | Information & communication | 2002 |
| Loky Holdings Ltd | Hospitality | 2024 |
| Lolly Lane Limited | Real estate | 2018 |
| Londinou 23 Limited | Real estate | 2025 |
| London Advanced Ceramics Ltd | Wholesale & retail | 2014 |
| London Elec Ltd | Construction | 2018 |
| London Electronic Limited | Manufacturing | 2000 |
| London LUX Driven Limited | Other services | 2022 |
| London Medical Training Ltd | Education | 2018 |
| London Motor Associates Ltd | Administrative & support | 2010 |
| London Property Company PLC | Extraterritorial | 1985 |
| London School of Biodynamic Psychotherapy (Gerda Boyesen Method ) Limited | Education | 2000 |
| London Wooden Stairs Limited | Construction | 2014 |
| Longmane Limited | Extraterritorial | 2005 |
| Longmeadow Widford Management Company Ltd | Real estate | 2022 |
| Longvale Properties Limited | Construction | 2005 |
| Longwood Road Management Company Limited | Households | 1985 |
| Loop Knitting Limited | Wholesale & retail | 2014 |
| Lord Street Properties (Southport) Limited | Real estate | 1896 |
| Lorraine Court (Southgate) Limited | Households | 1994 |
| Lost Images Ltd | Arts & recreation | 2013 |
| Lost Music Limited | Arts & recreation | 2002 |
| Lost Town Music Ltd | Arts & recreation | 2010 |
| Lost Words Ltd | Arts & recreation | 2013 |
| Lotus 15 Property Limited | Real estate | 2021 |
| Loudon Sainthill Ltd | Wholesale & retail | 2025 |
| Loulourox Aesthetics Ltd | Other services | 2023 |
| Lousa Properties Ltd | Real estate | 2005 |
| Love Camden Ltd | Wholesale & retail | 2011 |
| Love Rubbish Limited | Water & waste | 2026 |
| Lowton Consultancy Limited | Professional & scientific | 2014 |
| Loxwood Meadworks Ltd | Manufacturing | 2018 |
| Loyalty Financial Limited | Professional & scientific | 2016 |
| LP TV Ltd | Information & communication | 2022 |
| Lp.C. QS Services Limited | Professional & scientific | 2018 |
| LR 3 ST Germans RD Ltd | Real estate | 2024 |
| LS Carpentry & Construction Ltd | Construction | 2023 |
| LS IT Limited | Manufacturing | 2008 |
| LS IT Professionals Limited | Information & communication | 2019 |
| Lucid Dynamics Limited | Professional & scientific | 2009 |
| Luckystar Capital Ltd | Wholesale & retail | 2025 |
| Luckyways LP | | 2026 |
| Lucy Jones Broadcasting Limited | Information & communication | 2013 |
| Lugiv Limited | Other services | 2019 |
| Lulaband UK Ltd | Manufacturing | 2026 |
| Lulu Light Limited | Information & communication | 2024 |
| Lulu Sounds Ltd | Wholesale & retail | 2024 |
| Lulu's Pet Pantry Ltd | Wholesale & retail | 2022 |
| Luna Care Services Ltd | Health & social care | 2019 |
| Luna Therapy Limited | Health & social care | 2018 |
| Lunaelle Limited | Wholesale & retail | 2025 |
| Lunar Scenery Ltd | Arts & recreation | 2024 |
| Lunar Supply Co Ltd | Wholesale & retail | 2025 |
| LUX Manor Limited | Real estate | 2018 |
| Luxa Domus Ltd | Wholesale & retail | 2023 |
| Luxex Ltd | Wholesale & retail | 2014 |
| Luxuryblvd Ltd | Wholesale & retail | 2024 |
| LV Dean Limited | Information & communication | 2025 |
| LV Ltd | Real estate | 2004 |
| Lvtr Property Limited | Real estate | 2024 |
| LWH Clinical Limited | Professional & scientific | 2026 |
| Lyceum Management Limited | Households | 2003 |
| Lyttle Vibes Ltd | Wholesale & retail | 2021 |
| M & J Anastasi Property Partnership Ltd | Real estate | 2021 |
| M & N Bookkeeping & Accounting Services Limited | Professional & scientific | 2025 |
| M & T Sheet Metal Limited | Manufacturing | 1994 |
| M F Anastasis Limited | Financial services | 2022 |
| M Ignat Ltd | Administrative & support | 2017 |
| M K Freight Services (UK) Ltd | Transport & logistics | 2013 |
| M Mulvany Trading AS Mister Tacho Limited | Professional & scientific | 2017 |
| M&D POS Consultants Limited | Information & communication | 2023 |
| M&M Sisters Ltd | Health & social care | 2018 |
| M-Powered Limited | Health & social care | 2016 |
| M. & J. Engineers Limited | Professional & scientific | 1955 |
| M. & J. Hire Centres Limited | Professional & scientific | 1987 |
| M. Duffin Consulting Ltd | Professional & scientific | 2025 |
| M. Salida (London) Limited | Real estate | 2006 |
| M.C. Stone Limited | Administrative & support | 1999 |
| M25 Car Repair Ltd | Wholesale & retail | 2023 |
| M3 Exhibition Services Limited | Administrative & support | 2018 |
| Ma&Jo Building Services Ltd | Construction | 2021 |
| MAC and MOO Ltd | Wholesale & retail | 2022 |
| MAC Sports Management International Limited | Professional & scientific | 2018 |
| Macaw-Play CIC | Health & social care | 2025 |
| Mace Nest Ltd | Real estate | 2023 |
| Macrame Springknots Ltd | Professional & scientific | 2021 |
| Madanski Limited | Construction | 2013 |
| Made in Provence Limited | Wholesale & retail | 2009 |
| Madgecourt Limited | Real estate | 1981 |
| Magada Consultancy Ltd | Professional & scientific | 2024 |
| Magic Friends Ltd | Agriculture & fishing | 2023 |
| Magma Files Limited | Professional & scientific | 2025 |