| London Academy for Business and Entrepreneur Limited | Professional & scientific | 2016 |
| London Building and Refurbishments Team Limited | Construction | 2025 |
| London Felt Roofing Limited | Construction | 2016 |
| London Flat Roofing Limited | Construction | 2025 |
| London Hire Community Services Limited | Transport & logistics | 2013 |
| London Hire Limited | Administrative & support | 1983 |
| London Hire Sales Limited | Administrative & support | 2014 |
| London Mainscape Ltd | Construction | 2024 |
| London Spine & Pain Centre Limited | Health & social care | 2017 |
| Londondecor&Co Ltd | Construction | 2025 |
| Lopes Tiling Ltd | Construction | 2012 |
| Lopg Trading Limited | Extraterritorial | 2015 |
| Lordesland Nurseries Limited | Education | 2021 |
| Lorděsland Limited | Health & social care | 2024 |
| Lore Anne Ltd | Wholesale & retail | 2024 |
| Loridana Ltd | Transport & logistics | 2022 |
| Lorys Kevyn Limited | Construction | 2026 |
| Lotanne Ltd | Real estate | 2021 |
| Louros Limited | Professional & scientific | 2018 |
| Love AI Solutions Ltd | Information & communication | 2025 |
| Lovechris Services Ltd | Wholesale & retail | 2021 |
| Lovepreet Singh Ltd | Construction | 2021 |
| LRD Plumbing and Heating Ltd | Construction | 2010 |
| LTC Social Care Ltd | Health & social care | 2019 |
| Lubek Properties Limited | Construction | 2007 |
| Lublin Construction Ltd | Construction | 2022 |
| Luca TRANSPORT16 Logistic Ltd | Transport & logistics | 2022 |
| Lucy MAY Equity Limited | Real estate | 2021 |
| LUK Interiors Ltd | Construction | 2026 |
| Lume INT Ltd | Professional & scientific | 2009 |
| Luna Building & Civil Engineering Limited | Construction | 2013 |
| Lunar Shadow Ltd | Wholesale & retail | 2023 |
| Lush LAB Ltd | Other services | 2022 |
| Luxe Lounge LDN Limited | Wholesale & retail | 2025 |
| Luxe Panache Ltd | Construction | 2026 |
| Luxehaven Realty Limited | Real estate | 2024 |
| LUZ Franz Limited | Other services | 2024 |
| LVE Network Ltd | Other services | 2024 |
| LVM Marketing Ltd | Professional & scientific | 2025 |
| Lyfem Home Care Services UK Ltd | Administrative & support | 2017 |
| Lynchpin Storage Holdings Limited | Transport & logistics | 2023 |
| L’Able Ltd | Hospitality | 2025 |
| M & F Investments Limited | Professional & scientific | 1986 |
| M & M Healthy Living Designs Limited | Wholesale & retail | 2004 |
| M Hills Contractors Limited | Construction | 2018 |
| M K Autobreakers Limited | Wholesale & retail | 2012 |
| M Luxury Ltd | Wholesale & retail | 2026 |
| M T Clean Ltd | Administrative & support | 2022 |
| M Thind Ltd | Health & social care | 2023 |
| M&F Chef Services Limited | Other services | 2022 |
| M&H Trainings Ltd | Education | 2021 |
| M&S Info Solutions Limited | Real estate | 2019 |
| M'S Cuisine Ltd | Hospitality | 2024 |
| M- Health Care Service Ltd | Health & social care | 2022 |
| M2SEAN Limited | Health & social care | 2021 |
| MA Clinical Services Limited | Health & social care | 2026 |
| Maanewa Ltd | Hospitality | 2026 |
| Mafco Consult Limited | Professional & scientific | 2022 |
| Mafz Property Ltd | Real estate | 2023 |
| Magic Bakers London Ltd | Hospitality | 2018 |
| Magmart Ltd | Wholesale & retail | 2024 |
| Magnificent Touch Cleaners Ltd | Administrative & support | 2024 |
| Magnificent Touch Services Ltd | Health & social care | 2024 |
| Maianis Limited | Construction | 2025 |
| Maison Kassir Ltd | Wholesale & retail | 2022 |
| Maison Mariant Properties Ltd | Real estate | 2025 |
| Majestic Body Repairs Ltd | Wholesale & retail | 2025 |
| Majestic Customz Ltd | Wholesale & retail | 2022 |
| Make Workplace Limited | Administrative & support | 2020 |
| Making Moments Last Ltd | Extraterritorial | 2025 |
| Malagra Limited | Manufacturing | 2025 |
| Malate Express Ltd | Construction | 2025 |
| Malbro Homes Ltd | Real estate | 2005 |
| Maltburton Limited | Real estate | 2022 |
| Malus Spedition Ltd | Transport & logistics | 2018 |
| Mamvel Limited | Health & social care | 2020 |
| MAN Station One Limited | Other services | 2025 |
| Manafu G Ltd | Construction | 2025 |
| Mandip Consulting Limited | Professional & scientific | 2006 |
| Mangiarbene Ltd | Wholesale & retail | 2018 |
| Manha's Kitchen Limited | Hospitality | 2024 |
| Manhaas Limited | Wholesale & retail | 2021 |
| Manna Enterprises Group Limited | Hospitality | 2025 |
| Manroy Engineering Limited | Extraterritorial | 2017 |
| Mansion House Properties Limited | Hospitality | 2017 |
| Mantra Consultancy Services Limited | Information & communication | 2015 |
| Mantra Group Ltd | Real estate | 2024 |
| Manveer Construction (UK) Ltd | Construction | 2021 |
| Maple and Moss Limited | Education | 2025 |
| Maple Counselling Services Ltd | Health & social care | 2025 |
| Marchant's Fire and Security Ltd | Construction | 2023 |
| Mardarr UK Limited | Health & social care | 2024 |
| Margareta Gabriela Zamfir Ltd | Administrative & support | 2026 |
| Maria Lashes Ltd | Other services | 2022 |
| Marian Pana Constructions Ltd | Construction | 2021 |
| Markin SFS Ltd | Construction | 2021 |
| Martimari Ltd | Manufacturing | 2014 |
| Marvel Chauffeurs Limited | Transport & logistics | 2014 |
| Marvelous Minds Club CIC | Education | 2026 |
| Marvid's Ltd | Energy | 2018 |