| Living Nutrition Ltd | Administrative & support | 2014 |
| Livsana Ltd | Other services | 2020 |
| LIZ Reader Communications Limited | Professional & scientific | 2007 |
| Lizards Cricket Club Limited | Arts & recreation | 2021 |
| LJW Health Ltd | Financial services | 2026 |
| LL Accounting Ltd | Professional & scientific | 2016 |
| Lldh Services Limited | Health & social care | 2017 |
| Lloyd Boswell Limited | Administrative & support | 2010 |
| Lloyd’S Garden Care Limited | Financial services | 2022 |
| LLT Consulting Services Limited | Professional & scientific | 2025 |
| Lock Assist Limited | Administrative & support | 2013 |
| Lockd Self Storage Ltd | Transport & logistics | 2024 |
| Lodestar FS Limited | Information & communication | 2024 |
| Logicspace Limited | Information & communication | 1995 |
| Logistical Planners Europe Ltd | Professional & scientific | 2014 |
| Logplan (UK) Limited | Professional & scientific | 2014 |
| Logplan Europe Limited | Professional & scientific | 2014 |
| London Associates Ltd | Professional & scientific | 2020 |
| London Bakers Limited | Administrative & support | 2010 |
| London Road Storage Ltd | Transport & logistics | 2018 |
| Lonfork Limited | Households | 1980 |
| Longmead House Limited | Information & communication | 1997 |
| Lookout Brighton CIC | Education | 2018 |
| LOU Nash Radio Ltd | Information & communication | 2022 |
| Louisa Payne Ltd | Health & social care | 2026 |
| Louise Beasley Limited | Professional & scientific | 2024 |
| Louise Mulgrew Designs Limited | Arts & recreation | 2017 |
| Louise Mulgrew Limited | Arts & recreation | 2019 |
| Lovedog Recordz Limited | Information & communication | 2023 |
| Lovell Sinclair Limited | Professional & scientific | 2023 |
| Lovely Trading Limited | Wholesale & retail | 2011 |
| Loveursoul Limited | Health & social care | 2009 |
| Loveursoul [UK] Limited | Health & social care | 2013 |
| Lowe Electrical Limited | Construction | 2001 |
| Lowlever Ltd | Financial services | 2014 |
| Loxley House Ltd | Professional & scientific | 2021 |
| Lsmedical Ltd | Health & social care | 2019 |
| LSR Prop Limited | Real estate | 2024 |
| Lucky Bucket Productions Limited | Arts & recreation | 2009 |
| Lucky Fortune Cookie Co Limited | Manufacturing | 2005 |
| LUD Services Limited | Construction | 2017 |
| Luggage Glove Ltd | Wholesale & retail | 2023 |
| Luis Vidal Architects Ltd | Professional & scientific | 2025 |
| Luke Stevens Plumbing & Heating (South East) Limited | Construction | 2018 |
| Lumotrix Ltd | Manufacturing | 2012 |
| Lune Éire Investments Ltd | Real estate | 2025 |
| Lutine Bell Ltd | Administrative & support | 2010 |
| Luxe Comms Limited | Professional & scientific | 2015 |
| Luxe Signature Build Ltd | Construction | 2024 |
| Luxiri Ltd | Wholesale & retail | 2024 |
| Luxury Timepieces (UK) Ltd | Wholesale & retail | 1997 |
| LVR Recycling Ltd | Wholesale & retail | 2025 |
| Lyle Ammon Limited | Professional & scientific | 2022 |
| Lyle Consulting Ltd | Real estate | 2012 |
| M & C Promotions Ltd | Other services | 2021 |
| M & H Property Rentals Limited | Real estate | 2019 |
| M Everdell Plastering Services Ltd | Construction | 2012 |
| M J Wood Solutions Limited | Agriculture & fishing | 2006 |
| M Lets Ltd | Real estate | 2025 |
| M M Cruz Developments Limited | Construction | 2014 |
| M Pakdel Limited | Administrative & support | 2025 |
| M&H Go Gourmet Limited | Hospitality | 2023 |
| M&J Group Limited | Wholesale & retail | 2026 |
| M&M Legal Projects Ltd | Professional & scientific | 2019 |
| M&O Horizon Investments Limited | Financial services | 2026 |
| M-X Design Limited | Professional & scientific | 1996 |
| M. O’Connor Drylining Limited | Construction | 2022 |
| M.& R.Investments(Hassocks)Limited | Real estate | 1954 |
| M.Berwick & SON Flooring Ltd | Construction | 2024 |
| M.James Development Limited | Real estate | 2013 |
| M.M. Property Developers Limited | Real estate | 2014 |
| M23LAW Limited | Professional & scientific | 2022 |
| M9 Digital Ltd | Information & communication | 2012 |
| MA Kitchen Installations Limited | Construction | 2013 |
| MA Production Services Ltd | Professional & scientific | 2024 |
| Maad Concept Ltd | Professional & scientific | 2023 |
| Maatco Ltd. | Wholesale & retail | 2023 |
| Macen Associates Ltd | Professional & scientific | 2020 |
| Macen Developments Ltd | Construction | 2022 |
| Macen Land & Property Ltd | Real estate | 2023 |
| Macintyre Management Services Limited | Professional & scientific | 2017 |
| Macneal Medical Limited | Education | 2016 |
| MAD Robot Limited | Professional & scientific | 1998 |
| Madbomb Records Ltd | Information & communication | 2026 |
| Made and Making Ltd | Education | 2019 |
| Maidenbower Design Limited | Construction | 1987 |
| Major Plumbing and Heating Limited | Construction | 2002 |
| Major Property Rentals Ltd | Real estate | 2016 |
| Makn Properties Ltd | Real estate | 2025 |
| Makopia Ltd | Information & communication | 2010 |
| Malcolm Roberts Lighting Design Ltd | Information & communication | 2018 |
| Mallus Fresh Meat and Fish Delivery Ltd | Wholesale & retail | 2023 |
| Maltby Land Surveys Limited | Professional & scientific | 2000 |
| Mamorris Limited | Information & communication | 1998 |
| Mamouth Limited | Real estate | 2018 |
| Manalo Enterprise Limited | Administrative & support | 2019 |
| Mancini Photography Agency Limited | Professional & scientific | 2023 |
| Mane Limited | Manufacturing | 1971 |
| Manifold IT Limited | Information & communication | 2007 |
| Manju PVT Limited | Real estate | 2022 |