| Little Needs Ltd | Households | 2023 |
| LIV X Media Ltd | Professional & scientific | 2021 |
| Live Learn Grow CIC | Professional & scientific | 2025 |
| Live Well Ltd | Health & social care | 2025 |
| Livewel Care Ltd | Health & social care | 2025 |
| Living Plus Care Services Limited | Administrative & support | 2020 |
| Liviu Logistics Ltd | Transport & logistics | 2014 |
| Livium Limited | Construction | 2022 |
| Livs Solutions Ltd | Information & communication | 2023 |
| LJ Finance Limited | Financial services | 2014 |
| LJ Swim Schools Ltd | Education | 2025 |
| Ljelectricalservices Ltd | Construction | 2023 |
| LJH Projects and Properties Ltd | Construction | 2025 |
| LK Aura Limited | Wholesale & retail | 2025 |
| LK9'S Groom Room Limited | Other services | 2022 |
| LL Construction Ltd | Construction | 2026 |
| Lloyd Baker Group Limited | Financial services | 2022 |
| Lloyd Baker Leather Ltd | Wholesale & retail | 2011 |
| Lloyd Baker Stevenage Ltd | Real estate | 2019 |
| LME Consultancy Limited | Other services | 2019 |
| LMS Partners Limited | Arts & recreation | 2014 |
| LMT Confined Space Rescue Services Ltd | Construction | 2024 |
| LMW Racing Ltd | Arts & recreation | 2025 |
| LMY Bliss Ltd | Households | 2025 |
| Locum Imaging Diagnostics Limited | Health & social care | 2025 |
| Loff Ltd | Education | 2022 |
| Logical Mind Properties Ltd | Real estate | 2025 |
| Logical Mind Technologies Ltd | Information & communication | 2019 |
| Logistic Cucos Limited | Wholesale & retail | 2020 |
| Lomas Intumescent Paint Ltd | Construction | 2024 |
| Lomas Site Welding Ltd | Construction | 2022 |
| Lomas Special Projects Ltd | Construction | 2022 |
| Lomas Steel Structures Ltd | Construction | 2008 |
| London & Herts Holdings Ltd | Financial services | 2021 |
| London & Herts Ltd | Construction | 2019 |
| London Academy of Medical Science Ltd | Education | 2022 |
| London Culture and Education Committee (UK) Limited | Professional & scientific | 2026 |
| London Geo-Environmental Services Ltd | Professional & scientific | 2023 |
| London Haulage Limited | Transport & logistics | 2009 |
| London Multitraders Limited | Construction | 2023 |
| London Prime Properties Ltd | Construction | 2019 |
| London Recycling Solutions Limited | Water & waste | 2017 |
| Longevity Systems Limited | Administrative & support | 2025 |
| Lord Charles Oakleigh Estates Ltd | Real estate | 2016 |
| Lord DEE Logistics Limited | Transport & logistics | 2025 |
| Lord Kitchens Ltd | Other services | 2021 |
| Lorenzo Levrini Cinematography Limited | Information & communication | 2019 |
| Lotus Dwellings Limited | Real estate | 2013 |
| Louis & Bruno Limited | Information & communication | 2018 |
| Louisetrans Ltd | Transport & logistics | 2019 |
| Love More Ltd | Construction | 2020 |
| Love Without Walls Film Limited | Information & communication | 2020 |
| Loveena Ltd | Real estate | 2026 |
| Lovelay Graphics Ltd | Professional & scientific | 2024 |
| Low-Cost Removals Services Ltd | Transport & logistics | 2024 |
| Lrwh Limited | Information & communication | 2021 |
| LS Consultants Info LLP | | 2011 |
| LS6 Solutions Ltd | Construction | 2022 |
| Lsls Services Ltd | Administrative & support | 2022 |
| Luca Pacioli Business Solutions Ltd | Professional & scientific | 2022 |
| Lucafix Limited | Wholesale & retail | 2019 |
| Lucaj Building Services Limited | Construction | 2019 |
| Lucang Trans Ltd | Transport & logistics | 2016 |
| Lucky Cat 3 Ltd | Construction | 2021 |
| Lucy Murray Consulting Ltd | Professional & scientific | 2013 |
| Ludwick Group Limited | Financial services | 2025 |
| Lukmatic Services Ltd | Administrative & support | 2011 |
| Luminari Limited | Wholesale & retail | 2025 |
| Lumora Haven Care Ltd | Health & social care | 2026 |
| Luna Capital Holdings Ltd | Financial services | 2026 |
| Luna Consulting Services Ltd | Professional & scientific | 2026 |
| Luna Properties Group Ltd | Real estate | 2026 |
| Luna Trading Group Ltd | Professional & scientific | 2026 |
| Luprop Limited | Households | 1977 |
| Lush Design Maintenance Limited | Administrative & support | 2003 |
| Lush Heat Treatment Holdings Limited | Financial services | 2022 |
| Lush Industries Limited | Financial services | 2022 |
| Luxe Build 4U Limited | Construction | 2025 |
| Luxe Create&Build Ltd | Construction | 2017 |
| Luxeform Limited | Extraterritorial | 2023 |
| Luxtrade (Maintenance Products) Limited | Financial services | 1989 |
| Luxure Collective Ltd | Arts & recreation | 2025 |
| Luxury Cars (UK Export Agent) Ltd | Wholesale & retail | 2012 |
| Lwsoulutions Ltd | Professional & scientific | 2024 |
| Lycan Engineering Limited | Financial services | 2023 |
| LYF Ltd | Wholesale & retail | 2021 |
| Lynco Property Limited | Administrative & support | 2022 |
| Lynn Technologies Ltd | Information & communication | 2025 |
| Lyonblack Ltd | Wholesale & retail | 2025 |
| Lyons Care Recruitment Ltd | Public administration | 2025 |
| Lyonsdown Road Property Management Company Limited | Real estate | 1964 |
| Lyra Management Property Limited | Households | 2022 |
| LYW Limited | Professional & scientific | 2016 |
| M & a Jupp Limited | Professional & scientific | 2014 |
| M & D Jordan Limited | Wholesale & retail | 2007 |
| M and M Recruitment Ltd | Health & social care | 2024 |
| M H Forum Link Ltd | Professional & scientific | 1996 |
| M R Eden Properties Limited | Real estate | 2025 |
| M R Services (London) Ltd | Wholesale & retail | 2021 |
| M Services Limited | Extraterritorial | 1999 |