| Light Fixation Limited | Wholesale & retail | 2015 |
| Lightcast UK Ltd. | Information & communication | 2014 |
| Lightfoot Marketing Communications Limited | Administrative & support | 1995 |
| Lighting Controls Farnham Limited | Professional & scientific | 2014 |
| Lightningfast Limited | Other services | 2006 |
| Lightroom Photography Limited | Professional & scientific | 2021 |
| Lilijo Ltd | Manufacturing | 2021 |
| Lilly Gomm Limited | Administrative & support | 2016 |
| Lily James Homes Ltd | Real estate | 2014 |
| Limacus Ltd | Real estate | 2019 |
| Limax Ltd | Financial services | 2019 |
| Limax Studios Ltd | Information & communication | 2015 |
| Lime & ASH Ltd | Wholesale & retail | 2024 |
| Lime Accountancy Limited | Professional & scientific | 2007 |
| Lime Warner Limited | Financial services | 2024 |
| Limes Place Ltd | Real estate | 2019 |
| Linchpin Productions Limited | Professional & scientific | 2012 |
| Lincoln Park Ltd | Professional & scientific | 2009 |
| Linden Homes Limited | Construction | 1963 |
| Linear Time Machines Limited | Manufacturing | 2017 |
| Links M&E Recruitment Limited | Administrative & support | 2019 |
| Lion Biomed Limited | Administrative & support | 2022 |
| Lion Car Hub Ltd | Wholesale & retail | 2021 |
| Lion Gate Homes Limited | Real estate | 2015 |
| Lioncross Churt Ltd | Real estate | 2020 |
| Lioncross Partnership Ltd | Real estate | 2016 |
| Lioncross Properties Limited | Real estate | 2001 |
| Liquid Fusion Limited | Wholesale & retail | 2012 |
| Liquid Fusion Manufacturing Limited | Administrative & support | 2021 |
| Liquid Technology Limited | Information & communication | 2015 |
| Literary Legacies Limited | Information & communication | 2009 |
| Lith-Tech Ltd | Other services | 2017 |
| Little 5 Accounting Services Ltd | Professional & scientific | 2026 |
| Little Lighthouse Procurement Ltd | Professional & scientific | 2023 |
| Little Mead Capital Limited | Real estate | 2020 |
| Little S Investments Unlimited | Real estate | 2021 |
| Little Stodham Estate Limited | Households | 1966 |
| Littlestock Properties Ltd | Real estate | 2018 |
| Littlewick Developments Limited | Construction | 2021 |
| Liyali Ltd | Households | 2022 |
| LJ & FM Mattia Limited | Agriculture & fishing | 2010 |
| Lkcd Properties Ltd | Real estate | 2026 |
| Llangarron Assets Limited | Real estate | 2012 |
| Llennod Engineering Limited | Construction | 2013 |
| Lloyd Court (Wantage) Management Company Limited | Households | 1989 |
| Loaf Trustee Limited | Other services | 2025 |
| Localization Strategy Consulting Ltd | Professional & scientific | 2021 |
| Localthyme Property Management Limited | Real estate | 2003 |
| Locamed Limited | Administrative & support | 2000 |
| Location Communications Limited | Administrative & support | 1987 |
| Lochhead Holdings Limited | Financial services | 2019 |
| Locke Software Ltd | Extraterritorial | 2025 |
| Lockfast (Warrington) Limited | Wholesale & retail | 2004 |
| Lodestar Ltd | Information & communication | 2025 |
| Lofthouse Branding Limited | Other services | 2006 |
| Logistics for Hire Limited | Transport & logistics | 2025 |
| Londinium Fire & Security Ltd | Professional & scientific | 2023 |
| London Cruisers Limited | Administrative & support | 2015 |
| London Superyacht Show Limited | Professional & scientific | 2009 |
| London UX Limited | Professional & scientific | 2024 |
| Lonergan Associates Ltd | Professional & scientific | 2013 |
| Long Garden Place Land Limited | Households | 2017 |
| Long Hill Environment CIC | Professional & scientific | 2024 |
| Long Johns Limited | Information & communication | 2010 |
| Longdown Developments Ltd | Construction | 2010 |
| Longfleet Holdings Ltd | Real estate | 1965 |
| Longwood Associates LLP | | 2018 |
| Lookrite Limited | Construction | 2019 |
| Loop PR and Communications Ltd | Wholesale & retail | 2013 |
| Loopers Golf Club Ltd | Wholesale & retail | 2025 |
| Lorcal Limited | Professional & scientific | 2017 |
| Lords Caterers Limited | Hospitality | 2023 |
| Lotus Moon Ltd | Other services | 2025 |
| Louisa Elizabeth Limited | Wholesale & retail | 2020 |
| Louisa Stevens Consultancy Ltd | Administrative & support | 2023 |
| Love Accounts Limited | Professional & scientific | 2016 |
| Love Green Properties Limited | Real estate | 2026 |
| Love Stone Ltd | Administrative & support | 2020 |
| Love Your Retirement Limited | Professional & scientific | 2019 |
| Lovebugs Cafe Ltd | Hospitality | 2026 |
| Lovely Stuff Productions Limited | Professional & scientific | 2020 |
| LOW Energy Developments Limited | Construction | 2012 |
| Lowe & Campbell Publishing Ltd | Information & communication | 2008 |
| Lower Hale Properties Limited | Real estate | 2025 |
| Lower Manor Road Ltd | Households | 2014 |
| Loxwood (Mellow) Ltd | Real estate | 2021 |
| Loxwood Estates Limited | Real estate | 2023 |
| LP Bathrooms Ltd | Construction | 2021 |
| LP Electrical Installations Ltd | Construction | 2025 |
| LPF Properties Limited | Real estate | 2018 |
| LPF Supplies Limited | Administrative & support | 2015 |
| LRJ Aviation Services Limited | Professional & scientific | 2012 |
| LSC Education Ltd | Administrative & support | 2014 |
| LSD Design Limited | Administrative & support | 2005 |
| LSI Projects Limited | Construction | 1998 |
| Lszars Limited | Wholesale & retail | 2024 |
| LTE Building Ltd | Construction | 2024 |
| LTE Homes Ltd | Real estate | 2025 |
| Ltmb Limited | Extraterritorial | 2000 |
| Ltss Limited | Wholesale & retail | 2006 |