| LB Window Systems Ltd | Construction | 2019 |
| LBI Projects Ltd | Professional & scientific | 2024 |
| LC Cleaning Limited | Administrative & support | 2022 |
| Lcpm Holdings Ltd | Financial services | 2024 |
| LD Bioconsulting Limited | Professional & scientific | 2024 |
| LDG Consulting LLP | | 2024 |
| LDS Cambridge North Ltd | Other services | 2024 |
| Ldt-Build Limited | Construction | 2024 |
| LE Clay Roofing Ltd | Construction | 2015 |
| LE Sage Holdings Ltd | Real estate | 2026 |
| Leading Alpha Consulting Limited | Professional & scientific | 2017 |
| Lealans Limited | Real estate | 1957 |
| Lean Project Solutions Limited | Professional & scientific | 2014 |
| Leap and Dive Ltd | Information & communication | 2024 |
| Learn IT Online Limited | Information & communication | 2019 |
| Learnit Study Support Limited | Education | 2011 |
| Lecky Corporation Ltd | Wholesale & retail | 2025 |
| Lecturelinx EU Ltd | Information & communication | 2022 |
| Leda Group Limited | Financial services | 2019 |
| Leda Partnership Solutions Limited | Construction | 2014 |
| LEE Austin Globe Connect Limited | Professional & scientific | 2023 |
| LEE Builders Limited | Construction | 2003 |
| LEE Construction Builders Ltd | Construction | 2014 |
| Leeco Engineering Limited | | 1974 |
| Leighcrest Construction Limited | Construction | 2022 |
| Leisure Media Global Limited | Information & communication | 2020 |
| Lekman Consulting Ltd | Information & communication | 2013 |
| LEL Property Limited | Real estate | 2026 |
| Lemaro Precision Machining Limited | Manufacturing | 2010 |
| Lemonade HR Ltd | Professional & scientific | 2023 |
| Lenihan Construction Ltd | Construction | 2024 |
| Lenton Lettings Ltd | Real estate | 2024 |
| Leroy Alexander Smith Ltd | Construction | 2016 |
| Letchworth Family Golf Centre Limited | Hospitality | 2013 |
| Letts Property Group Ltd | Real estate | 2021 |
| Lewcon Audio Visual Ltd | Other services | 1999 |
| Lewcon Estates Limited | Real estate | 2021 |
| Lewesford House Management Company Limited | Households | 1990 |
| Lexical Consultancy Services Ltd | Health & social care | 2019 |
| Lexicon Fire Systems Limited | Public administration | 1995 |
| LEY Electrical Services Ltd | Manufacturing | 2018 |
| Leybourne Marketing Ltd | Wholesale & retail | 2016 |
| Leybourne Property Limited | Real estate | 2021 |
| LG Design Studio Ltd | Professional & scientific | 2019 |
| LH Engravers Ltd | Manufacturing | 2019 |
| Libby DIX Bespoke Services Ltd | Real estate | 2024 |
| Liberating Potential Limited | Professional & scientific | 2001 |
| Liberty Bishop (Denmark) Ltd | Information & communication | 2021 |
| Liberty Bishop (Finland) Ltd | Information & communication | 2007 |
| Liberty Bishop (Invoice and PAY Services) Ltd | Professional & scientific | 2015 |
| Liberty Bishop (Ireland) Ltd | Information & communication | 2007 |
| Liberty Bishop (Netherlands) Ltd | Information & communication | 2019 |
| Liberty Bishop (Sverige) Ltd | Information & communication | 2021 |
| Liberty Bishop International Ltd | Professional & scientific | 2017 |
| Licar Estates Limited | Real estate | 2005 |
| Lidder Investments Ltd | Real estate | 2004 |
| Lietpak UK Ltd | Administrative & support | 2016 |
| Life Internet Services Limited | Information & communication | 2021 |
| Life Laundry Design Limited | Wholesale & retail | 2018 |
| Lifestyle Emporium Ltd | Wholesale & retail | 2019 |
| Lightbox Holdings Limited | Financial services | 2020 |
| Lightbox Property Ltd | Real estate | 2023 |
| Lightbox Studio Limited | Administrative & support | 2018 |
| Lightbridge Analytics Ltd | Information & communication | 2019 |
| Lighthouse Hitchin Ltd | Hospitality | 2022 |
| Lighthouse Interior Solutions Limited | Real estate | 2014 |
| Lightning AID Limited | Extraterritorial | 2023 |
| Lightside Marketing Limited | Administrative & support | 2013 |
| Lightsout Computer Services Limited | Information & communication | 2003 |
| Lilley Star Limited | Professional & scientific | 2007 |
| Lillys Blooms Ltd | Wholesale & retail | 2025 |
| Lime House Media Limited | Information & communication | 2021 |
| Lime Tree Developments Limited | Real estate | 2011 |
| Limesharp Holdings Ltd | Financial services | 2025 |
| Limesharp Internet Limited | Information & communication | 2005 |
| Limited Edition Mondays Limited | Professional & scientific | 2012 |
| Limitless AV and Technology Limited | Information & communication | 2007 |
| Lindsell Avenue Residents Association Limited | Households | 2010 |
| Linemode Limited | Real estate | 1987 |
| Lingareddy's Ltd | Wholesale & retail | 2025 |
| Lingfield Place Limited | Real estate | 2018 |
| Link Education International | Education | 1995 |
| Link Play Therapy Limited | Extraterritorial | 2023 |
| Linxcroft Developments Limited | Construction | 1995 |
| Linxcroft Holdings Limited | Professional & scientific | 1994 |
| Liquid Goat Limited | Information & communication | 2014 |
| Litecastle Financial Services Limited | Financial services | 2003 |
| Litelines Direct Limited | Wholesale & retail | 2021 |
| Litelines Limited | Wholesale & retail | 2002 |
| Litestocks Limited | Wholesale & retail | 2018 |
| Litmus Analysis Limited | Professional & scientific | 2010 |
| Litmus Corporate Limited | Financial services | 2015 |
| Litmus Research Associates LLP | | 2011 |
| Little G'S Coffee Company Ltd | Wholesale & retail | 2021 |
| Little Monkey & Family Ltd | Hospitality | 2020 |
| Little Squirts PRE School Ltd | Education | 2014 |
| Little Train Business Development Ltd | Professional & scientific | 2024 |
| Little World Communications Limited | Professional & scientific | 2016 |
| Littlecote Ltd | Extraterritorial | 2014 |
| Living Room Design Ltd | Other services | 2017 |