| Lee-On-Solent Flying Group Limited | Transport & logistics | 2018 |
| Lee-Squared Limited | Real estate | 2026 |
| Leenane & Munsterbilzen Ltd | Professional & scientific | 2012 |
| Leereh Group Ltd | Wholesale & retail | 2023 |
| Lees Engineering Limited | Manufacturing | 2010 |
| Leftfield Events Ltd | Professional & scientific | 2008 |
| Legal Direct UK Limited | Manufacturing | 2014 |
| Legal Insights Limited | Administrative & support | 2018 |
| Legal Recourse Limited | Extraterritorial | 2015 |
| Legalito Limited | Information & communication | 2019 |
| Leigh Jones & Associates Ltd | Wholesale & retail | 2017 |
| Lellolu Ltd. | Information & communication | 2022 |
| Lemon BEE Limited | Professional & scientific | 2020 |
| Lennox Mall Management Ltd | Real estate | 2025 |
| LEO Media Ltd | Financial services | 2026 |
| Leon Professionals Ltd | Health & social care | 2023 |
| Leonard Investments Limited | Real estate | 1960 |
| Leonard Tobacco Company Limited | Professional & scientific | 1989 |
| Leonis Principal Ltd | Financial services | 2022 |
| Lerch Bates Ltd | Professional & scientific | 2014 |
| LES Caves DE Pyrene Limited | Wholesale & retail | 1995 |
| LES Caves Holdings Limited | Professional & scientific | 2010 |
| Lesley's Garden Limited | Manufacturing | 2025 |
| Lesmurdie Investments Limited | Real estate | 2021 |
| Lester Samuel Limited | Real estate | 2021 |
| LET ME Show YOU London Ltd | Administrative & support | 2019 |
| Let's Make This Happen Ltd | Administrative & support | 2025 |
| Levitas One Communities CIC | Health & social care | 2025 |
| Levskiwl Limited | Transport & logistics | 2023 |
| Levylsdene Residents Limited | Households | 1959 |
| Lewis & Barker Limited | Wholesale & retail | 1965 |
| Lewis & Hickey Limited | Professional & scientific | 1986 |
| Lewis Contractors Limited | Construction | 2013 |
| Lewis Daniels Services Limited | Administrative & support | 2026 |
| Lewis Tobacco Company Limited | Professional & scientific | 1989 |
| Lexa Survey Limited | Professional & scientific | 2016 |
| Lexitas Pharma Services UK Limited | Professional & scientific | 2023 |
| Lexstone Construction Limited | Construction | 2013 |
| Lezi Plastering & Drylining Ltd | Construction | 2025 |
| LFM Consulting Ltd | Information & communication | 2025 |
| LG Music Ltd | Manufacturing | 2022 |
| Lgbt Lawyers Limited | Professional & scientific | 2019 |
| LGC (Holdings) Limited | Administrative & support | 1995 |
| LGC (Japan) Limited | Professional & scientific | 1992 |
| LGC (North West) Limited | Professional & scientific | 1997 |
| LGC (Teddington) Limited | Professional & scientific | 2000 |
| LGC Genomics Limited | Professional & scientific | 2011 |
| LGC Group Holdings Limited | Professional & scientific | 2003 |
| LGC Investments Limited | Administrative & support | 2003 |
| LGC Limited | Professional & scientific | 1994 |
| LGC Scheme Pension Trustee Limited | Financial services | 2018 |
| LGC Science Corporation Limited | Financial services | 2019 |
| LGC Science Group Holdings Limited | Financial services | 2019 |
| LGC Science Group Limited | Professional & scientific | 2009 |
| LGC Science Holdings Limited | Administrative & support | 2010 |
| LGC Science Investments Limited | Administrative & support | 2009 |
| LGC Whirlwind Limited | Administrative & support | 2011 |
| LGN Unitied Ltd | Real estate | 2025 |
| LHA Coaching Ltd | Professional & scientific | 2019 |
| LHB Holdings Limited | Professional & scientific | 2000 |
| Lhla Limited | Households | 2006 |
| Lickpenny Limited | Professional & scientific | 2004 |
| Life Healthcare Communications Limited | Professional & scientific | 2000 |
| Life Made Simple Limited | Other services | 2006 |
| Lifescape Limited | Professional & scientific | 2015 |
| Lifestyle Care Services Limited | Health & social care | 2008 |
| Lifestyle First Ltd | Health & social care | 2024 |
| Lifestyle Mortgage Management Limited | Financial services | 2003 |
| Lifestyle Property Holdings Ltd | Real estate | 2017 |
| Liforma Ltd | Information & communication | 2026 |
| Light Gate Media Ltd | Information & communication | 2026 |
| Lightflows Limited | Information & communication | 2008 |
| Lighthouse Green Limited | Information & communication | 2023 |
| Lighting Direct Limited | Wholesale & retail | 2018 |
| Lightning Locations Ltd | Information & communication | 2016 |
| Lightswitch Ltd | Hospitality | 2015 |
| Liife.Io Limited | Information & communication | 2021 |
| Like IT Live Limited | Arts & recreation | 2010 |
| LIL Rigging Ltd | Construction | 2025 |
| Lilac Bottles Ltd | Wholesale & retail | 2024 |
| Lili Cleaning Services Ltd | Administrative & support | 2021 |
| Lilian's Flowers Limited | Wholesale & retail | 2023 |
| Lillington Properties Ltd | Real estate | 2016 |
| Lillington Property Services Limited | Real estate | 2017 |
| Lillypad Plumbing and Heating Ltd | Extraterritorial | 2010 |
| Lily Rose Cottages Limited | Hospitality | 2022 |
| Lily's Payroll Ltd | Professional & scientific | 2015 |
| Lilypad Plumbing Ltd | Extraterritorial | 2013 |
| Lime Construction (Guildford) Ltd | Construction | 2014 |
| Limen Altus Advisory Ltd | Professional & scientific | 2026 |
| Limiless Home and Garden Renovations Ltd | Construction | 2026 |
| Limitless Luxury Ltd | Administrative & support | 2024 |
| Limitless Property Holdings Limited | Construction | 2024 |
| Linen and Lichen Ltd | Professional & scientific | 2025 |
| Lingotto I LLP | | 2021 |
| Linklaser Limited | Manufacturing | 2020 |
| Linnerlake Limited | Manufacturing | 1978 |
| Linuk Ltd | Information & communication | 2012 |
| Lionark Limited | Real estate | 2009 |
| Lioncrest Capital Ltd | Financial services | 2025 |