| Kwik Investments Ltd | Financial services | 2023 |
| Kwik Picks Motors Ltd | Wholesale & retail | 2025 |
| KX4 Investments Limited | Financial services | 2021 |
| KYK Contractors Limited | Construction | 2008 |
| KYK Trading Limited | Wholesale & retail | 2019 |
| Kyza Properties Ltd | Real estate | 2024 |
| KZW4 Limited | Arts & recreation | 2014 |
| L & KA Management Ltd | Real estate | 2025 |
| L & V Property Limited | Real estate | 2025 |
| L F Heating & Plumbing Ltd | Construction | 2015 |
| L J Sawyer Consulting Ltd | Professional & scientific | 2026 |
| L Shape Extension Ltd | Construction | 2019 |
| L&A Architecture and Construction Ltd | Construction | 2025 |
| L&A Drainage Limited | Water & waste | 2026 |
| L&A Security Services Ltd | Administrative & support | 2025 |
| L&B Urban Limited | Real estate | 2024 |
| L&R Kaya Limited | Real estate | 2024 |
| L&R SON Autos Ltd | Wholesale & retail | 2023 |
| L&T Consulting Limited | Professional & scientific | 2013 |
| L'S Sandwich Bar Ltd | Hospitality | 2023 |
| L.B. Beauty Limited | Other services | 2007 |
| LA Contracting Services Limited | Construction | 2004 |
| Labellaa Ltd | Wholesale & retail | 2023 |
| Ladotski & Sons Limited | Real estate | 2017 |
| Ladzragz Ltd | Wholesale & retail | 2019 |
| Lakeview Property Investors Limited | Real estate | 2025 |
| Land and Beyond Limited | Construction | 2020 |
| Landlord-Plus Solutions Euro Ltd | Real estate | 2000 |
| Landmark Property Investment Services Limited | Real estate | 2020 |
| Lanes Exclusive Homes Ltd | Real estate | 2020 |
| Lanes Exclusive Land Ltd | Real estate | 2021 |
| Lanes Property Agents Limited | Real estate | 1987 |
| Langton Roofing Ltd | Construction | 2025 |
| Lankester-Bell Properties Ltd | Households | 2020 |
| Laranjeira Ltd | Agriculture & fishing | 2026 |
| Last Laugh Ltd | Manufacturing | 2025 |
| Laura Groves Associates Ltd | Information & communication | 2009 |
| Laura Rathbone Limited | Administrative & support | 2021 |
| Laurel Sales Consultancy and Coaching Ltd | Construction | 2019 |
| Lavender BLU Limited | Other services | 2016 |
| Lavitalia Ltd | Real estate | 2018 |
| Lawnstead Limited | Professional & scientific | 1982 |
| Layerllux Ltd | Wholesale & retail | 2025 |
| Layston House Management Company Limited | Households | 2020 |
| Lazy Cleaning Ltd | Administrative & support | 2026 |
| Lazy Construction Limited | Construction | 2026 |
| LB Communications Ltd | Other services | 2019 |
| LB Drylining UK Limited | Construction | 2026 |
| LBE Ltd | Professional & scientific | 2020 |
| LBH Enterprises Ltd | Financial services | 2024 |
| Lbpg Investments Limited | Real estate | 2021 |
| LCO Solutions Limited | Construction | 2014 |
| LDN Gleams Ltd | Wholesale & retail | 2022 |
| LEA Valley Flooring Ltd | Wholesale & retail | 2023 |
| LEA Valley Garden Services Ltd | Administrative & support | 2024 |
| LEA Valley Growers' Association, Limited | Other services | 1912 |
| LEA Valley Home Improvements Ltd | Administrative & support | 2026 |
| LEA Wharf Management Company Limited | Households | 2022 |
| Leading Minds Consultancy Ltd | Professional & scientific | 2022 |
| Learn Trade Skills Consultancy C.I.C. | Education | 2025 |
| Learn Trade Skills Ltd | Education | 2018 |
| Learning ROX Ltd | Education | 2019 |
| LEE Base Ltd | Other services | 2025 |
| LEE Bullen Engineering Limited | Manufacturing | 2016 |
| LEE Chapman Limited | Information & communication | 2017 |
| LEE Food Supplies Ltd | Wholesale & retail | 2021 |
| LEE Valley Paddlesports Club Ltd | Arts & recreation | 2014 |
| Leeds Lifescience Limited | Manufacturing | 2011 |
| Leemar Ductwork Limited | Construction | 1997 |
| Legacy Trading Limited | Administrative & support | 2015 |
| Legal Action Advisers Researchers and Achievers Ltd | Professional & scientific | 2025 |
| Legal Cost Analysts Limited | Professional & scientific | 2019 |
| Legal Solutions Euro Limited | Professional & scientific | 2002 |
| Legend Estates Limited | Real estate | 2025 |
| Legion Security Services Limited | Professional & scientific | 1982 |
| Lehane Security Systems Ltd | Administrative & support | 2019 |
| Leily Banan Limited | Other services | 1998 |
| Leisure Hours Limited | Real estate | 2025 |
| Leka Diesel Limited | Extraterritorial | 2014 |
| Leka Tyres Ltd | Wholesale & retail | 2005 |
| Lemon Dash Ltd | Households | 2025 |
| Lena Restaurant and Catering Limited | Hospitality | 2025 |
| Lending Hope Limited | Education | 2018 |
| Lenny's Executive Chauffeuring Ltd | Transport & logistics | 2024 |
| Leon Sales Ltd | Administrative & support | 2025 |
| Leonart UK Limited | Construction | 2019 |
| Lepaz Ltd | Administrative & support | 2014 |
| Let's Build Group Ltd | Construction | 2024 |
| LEV INS Britain Ltd | Professional & scientific | 2019 |
| LEV West Limited | Wholesale & retail | 2025 |
| Levbury Limited | Information & communication | 2022 |
| Level UP Meta Limited | Information & communication | 2024 |
| Levi Roots Ltd | Real estate | 2025 |
| Levon Homes Limited | Real estate | 2008 |
| Lexi Services Ltd | Construction | 2022 |
| Lexingtons North Finchley Ltd | Other services | 2014 |
| LFG Design Ltd | Professional & scientific | 2022 |
| LFM Studio Ltd | Financial services | 2024 |
| LG Surfacing Ltd | Construction | 2024 |
| LGM Homes Ltd | Real estate | 2021 |