| L J S Access Services Ltd | Mining & quarrying | 2023 |
| L J Taylor Industrial Ltd | Construction | 2023 |
| L Metcalf Services (UK) Limited | Extraterritorial | 2024 |
| L P Heating & Cooling Services Limited | Manufacturing | 2021 |
| L Ramsay Services Ltd | Other services | 2020 |
| L Story Electrical Ltd | Construction | 2020 |
| L&D Consultants Ltd | Wholesale & retail | 2024 |
| L.B.Bar Services Company Limited | Hospitality | 2019 |
| L.W Pipework Systems Ltd | Mining & quarrying | 2015 |
| LA Candy Yummy Cakes and Event Ltd | Hospitality | 2025 |
| LA Riviera NE Ltd | Hospitality | 2025 |
| LA Solutions Hub Limited | Energy | 2020 |
| Lagrenewables Ltd | Manufacturing | 2021 |
| Lake Pizza Limited | Hospitality | 2025 |
| Lakeaccessltd Ltd | Construction | 2025 |
| Lamb Conveyancing Services Ltd | Professional & scientific | 2024 |
| Lamb International Limited | Manufacturing | 1991 |
| Lambert Construction Ltd | Extraterritorial | 2021 |
| Lambert Gale Properties Limited | Households | 2022 |
| Land & Sea Technical Services Ltd | Professional & scientific | 2024 |
| Landj Rigging and Lifting Specialists Ltd | Construction | 2026 |
| Langdale Electrics Limited | Construction | 2025 |
| Langdale Projects Ltd | Construction | 2023 |
| Langkirk Limited | Real estate | 1992 |
| Larnelee Ltd | Wholesale & retail | 2023 |
| Lasting Legacy Leisure Ltd | Hospitality | 2024 |
| Late Night Menu Ltd | Hospitality | 2020 |
| Lauder Writing Limited | Information & communication | 2023 |
| Lawson's South Shields Limited | Other services | 2013 |
| Laycock Electrical Contractors Ltd | Construction | 2025 |
| Laycock Lettings Ltd | Construction | 2018 |
| Laygate Construction Ltd | Construction | 2024 |
| Laygate Distribution Ltd | Wholesale & retail | 2026 |
| Laygate Events Ltd | Hospitality | 2024 |
| Laygate Leisure Ltd | Hospitality | 2025 |
| Laygate Ltd | Construction | 2022 |
| LB Hospitality & Entertainment Consultancy Ltd | Professional & scientific | 2026 |
| LB Wind Services Ltd | Construction | 2018 |
| LC3 Investments Ltd | Real estate | 2026 |
| Lcrispy Ltd | Construction | 2024 |
| Ldwlocum Ltd | Health & social care | 2022 |
| Learning for Excellence Ltd | Education | 2016 |
| LEE Easton Limited | Professional & scientific | 2017 |
| LEE Fada Limited | Professional & scientific | 2012 |
| LEE Hartnack Ltd | Construction | 2016 |
| Lees Cleaning Contractors LLP | | 2009 |
| Lees Custom Woodwork and Design Ltd | Manufacturing | 2019 |
| Lees Premier Cleaning Ltd | Administrative & support | 2014 |
| Leighton Motors Car Sales Ltd | Wholesale & retail | 2011 |
| Leighton Motors Ltd | Wholesale & retail | 2011 |
| Lenny's Tackle & Bait Ltd | Wholesale & retail | 2021 |
| LEO94 Property Management Limited | Real estate | 2024 |
| Leonard Flooring & Home Ltd | Wholesale & retail | 2024 |
| Lets Recruit Limited | Administrative & support | 2024 |
| Level UP in Real Life Holding Company Ltd | Financial services | 2022 |
| Lewthwaite Contractors Ltd | Construction | 2023 |
| Lexden Group Ltd | Extraterritorial | 2022 |
| Lexden Property Developments Ltd | Construction | 2022 |
| Lfpc Limited | Hospitality | 2017 |
| Lgdi Ltd | Information & communication | 2016 |
| LH Coaching and Consulting Ltd | Professional & scientific | 2022 |
| LH Offshore Services Ltd | Manufacturing | 2023 |
| Lhfoodgalore Ltd | Wholesale & retail | 2026 |
| Lifestreamuk Limited | Health & social care | 2023 |
| Liftmaster Service Ltd | Wholesale & retail | 2007 |
| Lilly Enterprises Limited | Manufacturing | 2021 |
| Limitless Access Solutions Ltd | Construction | 2025 |
| Limitless Training & Nutrition Ltd | Professional & scientific | 2020 |
| Linc Engineering Limited | Professional & scientific | 2020 |
| Linenwing Limited | Information & communication | 2016 |
| Lite Vape Ltd | Manufacturing | 2026 |
| Little Comets LLP | | 2009 |
| Little Herd Events Limited | Arts & recreation | 2026 |
| Little Shed Events Ltd | Hospitality | 2024 |
| Liv's Skin Care N.E. Ltd | Other services | 2025 |
| Living Faith Limited | Real estate | 2025 |
| Living Waters Church South Tyneside | Other services | 2010 |
| LIZ Wright Educational Psychology Services Ltd | Education | 2024 |
| LJ Electrical Inspection Limited | Professional & scientific | 2017 |
| LJ Energy Ltd | Construction | 2022 |
| LJ Energy Surveys Ltd | Professional & scientific | 2023 |
| LJC Barbers Ltd | Real estate | 2021 |
| LJG Consultancy Ltd | Information & communication | 2024 |
| LJS Property Maintenance Limited | Administrative & support | 2023 |
| LJW03 Ltd | Construction | 2024 |
| LNV Rockstar Abseiling Solutions Limited | Construction | 2021 |
| Lock UPS for U Ltd | Real estate | 2023 |
| Lovabelle Franchising Limited | Education | 2023 |
| Lovabelle Limited | Education | 2023 |
| Lovel Property Ltd | Real estate | 2024 |
| LP Power Projects Ltd | Administrative & support | 2015 |
| Lpappa Limited | Construction | 2025 |
| LRS Coating NE Ltd | Administrative & support | 2025 |
| LS & DAN International Ltd | Wholesale & retail | 2015 |
| LS Wind Services Ltd | Manufacturing | 2019 |
| LSS Energy Ltd | Professional & scientific | 2026 |
| LST Coatings Ltd | Mining & quarrying | 2014 |
| Ltd Prime Group Ltd | Health & social care | 2026 |
| LTG Marine Limited | Extraterritorial | 2016 |
| Lucid Accounting Ltd | Professional & scientific | 2025 |