| Lift Training Centre Limited | Professional & scientific | 2026 |
| Lightmakers Sydenham Residents’ Management Company Limited | Households | 2025 |
| LIL Bo's Deli Limited | Wholesale & retail | 2023 |
| LIL Stars Childcare Services Limited | Health & social care | 2021 |
| Liminal Creates Ltd | Information & communication | 2026 |
| Lindmere Construction Limited | Extraterritorial | 1981 |
| Lindsey Holdings Limited | Real estate | 2019 |
| Linford Grey Associates Limited | Professional & scientific | 2013 |
| Lisa Lashes Limited | Arts & recreation | 2000 |
| List Transport Ltd | Transport & logistics | 2019 |
| Little Bay Real Estate Services (UK) Ltd | Real estate | 2018 |
| Little Johnny Limited | Information & communication | 2020 |
| Live Meno Ltd | Wholesale & retail | 2023 |
| LK Car Wash Services Limited | Administrative & support | 2025 |
| LK Mama Nutrition Ltd | Hospitality | 2025 |
| LLL Services Ltd | Transport & logistics | 2025 |
| LMA Properties (Groby) Limited | Real estate | 2015 |
| LOC8 a Space Ltd | Real estate | 2024 |
| Local Health Partners Ltd | Health & social care | 2026 |
| Lofaki Ltd | Real estate | 2019 |
| Logistic Provider (Academy&Transport) Ltd | Transport & logistics | 2021 |
| Logistics Connect Ltd | Transport & logistics | 2022 |
| Logson Holdings Limited | Professional & scientific | 2015 |
| Logson Limited | Financial services | 2010 |
| London and Northern Group Limited | Professional & scientific | 1961 |
| London Concrete Limited | Professional & scientific | 1997 |
| London Road Garage Holdings Ltd | Financial services | 2019 |
| London Road Garage Limited | Wholesale & retail | 2008 |
| Lost Property 25 Ltd | Wholesale & retail | 2025 |
| Lottie Laine Limited | Administrative & support | 2018 |
| LP Rails and Repairs Ltd | Manufacturing | 2024 |
| LPC Group (UK) Limited | Transport & logistics | 2010 |
| LPC Logistics Limited | Transport & logistics | 2015 |
| LPC Property Investments Limited | Real estate | 2024 |
| Lublair Ltd | Real estate | 2025 |
| Lubrication Limited | Wholesale & retail | 2001 |
| Lulu Belle Events Ltd | Hospitality | 2024 |
| Luminous Projects Limited | Education | 2024 |
| Lunaris 8 Ltd | Transport & logistics | 2025 |
| Lungu Manuel Ltd | Transport & logistics | 2019 |
| Lusso Veloce Ltd | Wholesale & retail | 2018 |
| Lustro Surveys Ltd | Professional & scientific | 2025 |
| Luxify Properties Ltd | Real estate | 2025 |
| Luxurious Hideaways Ltd | Extraterritorial | 2021 |
| LV Cargo Ltd | Transport & logistics | 2024 |
| Lynda Timson Investments Limited | Financial services | 2021 |
| Lytag Limited | Professional & scientific | 2006 |
| M & C Smart Holdings Ltd | Financial services | 2025 |
| M & C Smart Properties Ltd | Real estate | 2025 |
| M & D Metalwork Limited | Other services | 2018 |
| M & K DRY Cleaners Ltd | Other services | 2022 |
| M B Ahmad Ltd | Transport & logistics | 2018 |
| M D Site Services Limited | Construction | 2006 |
| M J Farrell & Sons Limited | Construction | 2009 |
| M J Flooring Services Limited | Construction | 2015 |
| M S Builders Leicester Ltd | Construction | 2014 |
| M Smart Properties Ltd | Real estate | 2016 |
| M&H 7 Group Ltd | Financial services | 2025 |
| M. & C. Jones & Company Limited | Construction | 1979 |
| M.Salah Ltd | Health & social care | 2025 |
| M.T.S Logistics Limited | Transport & logistics | 2012 |
| M.T.S. (Storage & Distribution) Limited | Real estate | 1986 |
| MA Aesthetics by Mary-Anne Ltd | Other services | 2026 |
| Maalkum Limited | Education | 2022 |
| Made Partnership LLP | | 2024 |
| Madeleine and Proper Tea Ltd | Real estate | 2018 |
| Maid 2 Sparkle Ltd | Administrative & support | 2020 |
| Maid Spotless Limited | Administrative & support | 2016 |
| Maison DE Dust Ltd | Manufacturing | 2025 |
| Majemil Healthcare Ltd | Health & social care | 2021 |
| Malak Homz Ltd | Real estate | 2024 |
| Malak Housing Ltd | Real estate | 2021 |
| Malak Properties Limited | Real estate | 2025 |
| Management Enterprises Ltd | Professional & scientific | 2004 |
| Mander Cruickshank Solicitors LLP | | 2007 |
| Mangan Financial Planning Ltd | Professional & scientific | 2024 |
| Manor GAS Services Ltd | Construction | 2019 |
| MAP Merchant Group Limited | Professional & scientific | 1998 |
| Marian Lipan Transport Limited | Transport & logistics | 2022 |
| Marios Pizza Coalville Ltd | Hospitality | 2023 |
| Mark Davis Optical Ltd | Health & social care | 2025 |
| Markfield Woodworking Machinery Limited | Wholesale & retail | 1983 |
| Marlow Proactive Limited | Professional & scientific | 2018 |
| Marmalade Couriers Ltd | Transport & logistics | 2024 |
| Marn Academy Limited | Education | 2023 |
| Marn Properties Ltd | Real estate | 2022 |
| Marple Development Company Limited | Professional & scientific | 1944 |
| Marques | Other services | 1988 |
| Martin Hier Limited | Financial services | 2013 |
| Martin International Ltd | Construction | 2019 |
| Marulu Ltd | Health & social care | 2023 |
| Massage & Movement Therapy Centre Limited | Health & social care | 2025 |
| Masterplan Travel Limited | Transport & logistics | 2025 |
| Matrix Procurement Ltd | Professional & scientific | 2025 |
| Matsuura Machinery Limited | Wholesale & retail | 1991 |
| Matthew Needham Limited | Administrative & support | 2010 |
| Mattuholl & SON Ltd | Real estate | 2021 |
| Matykey Transport Ltd | Transport & logistics | 2025 |
| MAX Cook 30 Limited | Arts & recreation | 2023 |
| Maxpad(Uk) Limited | Financial services | 2023 |