| Lakeside Container Services Ltd | Transport & logistics | 1996 |
| Lama Services Limited | Construction | 2022 |
| Land London Limited | Construction | 2017 |
| Land London Rental Limited | Real estate | 2022 |
| Lander Hayley Ltd. | Financial services | 1983 |
| Landon Costa Ltd | Professional & scientific | 2026 |
| Lanken (UK) Limited | Professional & scientific | 2011 |
| Lara ZEE Homes Limited | Real estate | 2020 |
| Larkfield (Group) Limited | Construction | 2008 |
| Latte to Go Ltd | Hospitality | 2013 |
| Leap Marketing Consultancy Limited | Administrative & support | 2008 |
| LEE MT Limited | Real estate | 2023 |
| LEE Porter Golf Solutions Ltd | Arts & recreation | 2005 |
| Legacy Refurbishment Ltd | Construction | 2022 |
| Leisure Creations Limited | Administrative & support | 2000 |
| Leisureworld (GB) Limited | Financial services | 1991 |
| Leonard Brinton Interiors Limited | Wholesale & retail | 2018 |
| Lifetime Properties Limited | Construction | 1994 |
| Lilla O’Connor Ltd | Professional & scientific | 2023 |
| Lillevilla (UK) Limited | Wholesale & retail | 2016 |
| Little Barn Café Ltd | Hospitality | 2021 |
| Littlebury Consulting Ltd | Professional & scientific | 2024 |
| LJ Digital and Data Consulting Ltd | Professional & scientific | 2018 |
| LJB Property Holdings Ltd | Real estate | 2024 |
| LM Events London Limited | Arts & recreation | 2018 |
| Lndc Limited | Health & social care | 2013 |
| Lobas Consulting Limited | Information & communication | 2014 |
| LOG Cabins Direct.Co.Uk Limited | Wholesale & retail | 2015 |
| Logistically Worldwide Ltd | Professional & scientific | 2019 |
| London Adelaide Ltd | Professional & scientific | 2026 |
| London and Essex Groundworks Ltd | Construction | 2026 |
| London Clearing Limited | Water & waste | 2008 |
| London Electrical and Data Ltd | Construction | 2020 |
| Longview Brothers Limited | Wholesale & retail | 2026 |
| Lotus Property Solutions Ltd | Real estate | 2019 |
| Louise B Design Ltd | Wholesale & retail | 2020 |
| Loulippe Limited | Real estate | 2021 |
| Lucas Farm Limited | Real estate | 2025 |
| Luxury Shared Living Limited | Construction | 2021 |
| Lykiafashion Limited | Wholesale & retail | 2023 |
| Lyndsay's Farm Livery Ltd. | Arts & recreation | 1996 |
| M & M Environmental Construction Limited | Construction | 2008 |
| M a AQ Limited | Financial services | 2024 |
| M Day FX & Treasury Ltd | Professional & scientific | 2019 |
| M L Eagle Contracts Limited | Construction | 2013 |
| M.W. Beer & Co. Limited | Wholesale & retail | 1981 |
| M2M Planet Limited | Real estate | 2022 |
| M2MDIGITAL Ltd | Wholesale & retail | 2015 |
| Mach Construction Services Ltd | Construction | 2015 |
| Mackie Group Limited | Professional & scientific | 2026 |
| MAD Consultancy and Events Limited | Arts & recreation | 2014 |
| Maddison Services Limited | Real estate | 2015 |
| Malcolm Connolly Security Ltd | Administrative & support | 2013 |
| Mally Consultants Limited | Administrative & support | 2019 |
| Manor Park Dementia Care Ltd | Health & social care | 2024 |
| Manor Park OP Co Ltd | Health & social care | 2025 |
| Manor Park Prop Co Ltd | Health & social care | 2025 |
| Mansion Care Ltd | Administrative & support | 1999 |
| Manta 2018 One Ltd. | Real estate | 2018 |
| Marbill Property Services Limited | Real estate | 2023 |
| Marie Stacey Interiors Limited | Professional & scientific | 2017 |
| Market Tyres Southend Limited | Wholesale & retail | 2004 |
| Marphil Capital Ltd | Real estate | 2018 |
| Martha & ME Limited | Manufacturing | 2025 |
| Martin FM Solutions Ltd | Construction | 2017 |
| Mathetes Consulting Limited | Professional & scientific | 2021 |
| Matohanci IT Services Limited | Information & communication | 2015 |
| MAX Fire Systems Limited | Construction | 1998 |
| MAY & Raeburn (Holdings) Limited | Financial services | 2025 |
| MAY & Raeburn (Petfood) Ltd | Wholesale & retail | 2024 |
| MAY & Raeburn Investments Limited | Real estate | 2013 |
| MB Accounting Solutions Limited | Professional & scientific | 2022 |
| Mcaw Limited | Other services | 2021 |
| Mcbean Health & Wellness Limited | Health & social care | 2015 |
| Mccp Investments Limited | Financial services | 2012 |
| Mcculloch Contracts Ltd | Construction | 2002 |
| Mcmillan Digital Ltd | Information & communication | 2020 |
| MD Roofing Contractors Limited | Construction | 2008 |
| Meli MC Limited | Professional & scientific | 2021 |
| Merebridge Consulting Ltd | Information & communication | 2025 |
| Metis Compliance Limited | Professional & scientific | 2018 |
| Mexecal Ltd | Wholesale & retail | 2024 |
| Mharsvpiluxurystays Ltd | Real estate | 2023 |
| MI 3D Limited | Other services | 2023 |
| Mias O.C (UK) Limited | Wholesale & retail | 2025 |
| Michael Stuart Associates Ltd | Professional & scientific | 2019 |
| Midland North Ltd | Real estate | 2017 |
| Mike Air Ltd | Construction | 2025 |
| Miles Away Group Ltd | Information & communication | 2022 |
| Millday Properties Limited | Real estate | 2003 |
| Millhurst Consulting Ltd | Professional & scientific | 2024 |
| Mind and Body London Ltd | Health & social care | 2019 |
| Mindfulness Millie Ltd | Health & social care | 2022 |
| Missano Services L.P. | | 2021 |
| Misto Barber Ltd | Other services | 2022 |
| Mkjt Limited | Real estate | 2024 |
| MLK Properties (Essex) Ltd | Real estate | 2025 |
| Mmultiply Ltd | Real estate | 2018 |
| Mobile Gym Fitness Ltd | Other services | 2018 |
| Monkey Tower Ltd | Manufacturing | 2003 |