| Leon DE ORO UK Ltd | Manufacturing | 2010 |
| Leon OC Holdings Limited | Financial services | 2026 |
| Leon OC Ltd | Other services | 2025 |
| Leopard Solutions Ltd | Professional & scientific | 2015 |
| Let's FIX IT Thame Limited | Other services | 2023 |
| Lets Deliver Ltd | Transport & logistics | 2019 |
| Leven Developments Limited | Real estate | 2020 |
| Levikay Ltd | Professional & scientific | 2012 |
| Lewes Consultants Ltd | Professional & scientific | 2011 |
| Lewis's Butchers Limited | Manufacturing | 2011 |
| Lewisgray Ltd | Professional & scientific | 2026 |
| Leyton House Properties Limited | Professional & scientific | 1989 |
| LH Health and Performance Ltd | Health & social care | 2026 |
| LHD Prestige Leasing Ltd | Administrative & support | 2016 |
| Liala Limited | Administrative & support | 2025 |
| Liam & Laura Limited | Administrative & support | 2023 |
| Liberty Horseboxes Limited | Wholesale & retail | 2006 |
| Liberty Services Limited | Health & social care | 2019 |
| Libratum Life Ltd | Professional & scientific | 2010 |
| Librestream Technologies (UK) Ltd | Information & communication | 2017 |
| Licence at Design Limited | Wholesale & retail | 2010 |
| Liftright Limited | Education | 2025 |
| Light Construction Limited | Construction | 2004 |
| Lightning Precision Engineering Limited | Professional & scientific | 2021 |
| LIL Legal Limited | Professional & scientific | 2022 |
| Lila Domestic Cleaning Service Ltd | Administrative & support | 2018 |
| Lilley-Brown Property Solutions Ltd | Real estate | 2022 |
| Lillywhite Construction Ltd | Construction | 2022 |
| Lilywood Advisory Ltd | Professional & scientific | 2025 |
| Lime Education Consulting Ltd | Education | 2023 |
| Lime Engineering Ltd | Professional & scientific | 2026 |
| Lina LO Ltd | Professional & scientific | 2024 |
| Linfield Grove Estates Limited | Households | 2025 |
| Linford House Management Company Limited | Households | 2013 |
| Lingua Lotta Ltd | Education | 2021 |
| Link Groundworks Bicester Limited | Construction | 2013 |
| Linnet Mansion (Freehold) Limited | Households | 2022 |
| Linora Nouveau Ltd | Wholesale & retail | 2025 |
| Lionel W Gibbs (Hornton) Limited | Manufacturing | 1980 |
| Listings Estate Agents Ltd | Real estate | 2004 |
| Little Chick Productions LLP | | 2021 |
| Little Elves Montessori Nursery School Ltd | Education | 2008 |
| Little GG Ltd | Wholesale & retail | 2020 |
| Little Grey Media Limited | Information & communication | 2020 |
| Little Learners Publishing Limited | Information & communication | 2011 |
| Little Self's Property LLP | | 2022 |
| Livekindly UK Ltd | Wholesale & retail | 2014 |
| LJ Ultimate Solutions Ltd | Administrative & support | 2023 |
| Ljbar Trading Limited | Hospitality | 2023 |
| LJD Conveyancing Ltd | Professional & scientific | 2026 |
| LJR Land & Holdings Ltd | Real estate | 2023 |
| LK Frain Builders & Decorators Limited | Administrative & support | 2015 |
| LKA Builders Limited | Construction | 2023 |
| LKB Property Ltd | Real estate | 2022 |
| Lkcd Limited | Health & social care | 2024 |
| LKD Property Investments Limited | Real estate | 2020 |
| LKT Electrical Services Limited | Construction | 2007 |
| Llandraw Farm Limited | Agriculture & fishing | 2016 |
| Llandraw Limited | Real estate | 2016 |
| LLJ Real Estate LLP | | 2014 |
| LMK Living Ltd | Construction | 2024 |
| Lmkr Property Ltd | Real estate | 2024 |
| LMY Therapy Ltd | Health & social care | 2024 |
| Local Trades App Ltd | Professional & scientific | 2025 |
| Locallyours Ltd | Information & communication | 2023 |
| Lockhart Garratt Limited | Agriculture & fishing | 1998 |
| Lodestar Realty Limited | Real estate | 2020 |
| Lodjer Limited | Real estate | 2018 |
| Loewe Contemporary Ltd | Arts & recreation | 2017 |
| Logi Direct Ltd | Wholesale & retail | 2024 |
| Logic Mill Ltd | Information & communication | 2025 |
| Logical Investments Ltd | Real estate | 2025 |
| Loncin Limited | Extraterritorial | 2015 |
| London & Home Counties Upholstery Limited | Other services | 2003 |
| London HIT Ltd | Wholesale & retail | 2018 |
| London Super Sports Limited | Education | 2022 |
| Longfield Management Company Limited | Households | 2012 |
| Longson Properties Ltd | Real estate | 2024 |
| Loomsy Limited | Wholesale & retail | 2025 |
| Lords & Ladies Banbury Limited | Other services | 2015 |
| Lotus Property Planet Ltd | Real estate | 2025 |
| Louie Rashier Limited | Wholesale & retail | 2022 |
| Louis Smit Limited | Health & social care | 2010 |
| Louloc Plumbing and Heating Ltd | Construction | 2020 |
| Love by Name Limited | Other services | 2013 |
| Love Candy Limited | Wholesale & retail | 2024 |
| Love Yachts Limited | Hospitality | 2022 |
| LOW Cost Electric Ltd | Professional & scientific | 2025 |
| Lowrieast Ltd | Wholesale & retail | 2026 |
| Lozi Woman Ltd | Real estate | 2022 |
| LRL Property Holdings Limited | Real estate | 2026 |
| LS Airmotive Limited | Transport & logistics | 2017 |
| LS Renovations Ltd | Construction | 2012 |
| Lsbc (London) Limited | Professional & scientific | 2003 |
| LTG Enterprises Limited | Professional & scientific | 2013 |
| Luckymehome Ltd | Real estate | 2025 |
| Luckyou Nail Lounge Ltd | Other services | 2025 |
| Luckyyou Lifestyle Ltd | Wholesale & retail | 2025 |
| Lucy Howard Dermatology Limited | Health & social care | 2024 |
| Luke Roper Distribution Limited | Wholesale & retail | 2007 |