| Kamtao (Restaurants) Limited | Real estate | 1972 |
| Kamtao Holdings Limited | Financial services | 1984 |
| Kamtao Properties Limited | Real estate | 1984 |
| Kashi Properties LLP | | 2026 |
| KEE Assets Ltd | Financial services | 2017 |
| Keepingco Ltd | Administrative & support | 2025 |
| Kemmz Ltd | Health & social care | 2025 |
| Kenwood Consulting Ltd | Administrative & support | 2023 |
| KEW Design Build Limited | Professional & scientific | 2010 |
| Keystone Strategy Ltd | Administrative & support | 2025 |
| Keywood Commerce Ltd | Wholesale & retail | 2023 |
| KFP (London) Limited | Professional & scientific | 2012 |
| Khaic Limited | Real estate | 2020 |
| KHAIC7 Limited | Other services | 2023 |
| Khaici Ltd | Financial services | 2024 |
| Khala Pizza Ltd | Hospitality | 2024 |
| Khaosarn Thai Cuisine Ltd | Hospitality | 2018 |
| KIA UK Limited | Wholesale & retail | 2002 |
| Kibosh Sports Tech Ltd | Education | 2021 |
| Kilmiah Limited | Real estate | 2026 |
| Kiloran Media Services Limited | Professional & scientific | 2012 |
| Kindminds Support Ltd | Health & social care | 2026 |
| Kingscote and Palace Investments Limited | Wholesale & retail | 2015 |
| Kingston Offices Ltd | Real estate | 2024 |
| Kingswater Securities Limited | Administrative & support | 2003 |
| Kiraston Ltd | Professional & scientific | 2025 |
| Kitsu Limited | Health & social care | 2026 |
| KJA Management Ltd | Professional & scientific | 2024 |
| Knight Managed Care Limited | Professional & scientific | 2022 |
| Knightscale Partners Ltd | Education | 2024 |
| Knowbotic AI Ltd | Professional & scientific | 2023 |
| Knowbotics AI Ltd | Professional & scientific | 2024 |
| Koko&Co Ltd | Wholesale & retail | 2025 |
| Kokoro Bedford Ltd | Hospitality | 2022 |
| Kokoro Caterham Ltd | Hospitality | 2022 |
| Kokoro Dorking Ltd | Hospitality | 2022 |
| Kokoro Durham Ltd | Hospitality | 2022 |
| Kokoro Eastleigh Ltd | Hospitality | 2022 |
| Kokoro EP Ltd | Hospitality | 2026 |
| Kokoro Farnborough Ltd | Hospitality | 2021 |
| Kokoro Franchise Ltd | Hospitality | 2017 |
| Kokoro Hastings Ltd | Hospitality | 2022 |
| Kokoro Hounslow Ltd | Hospitality | 2022 |
| Kokoro Joy Ltd | Hospitality | 2025 |
| Kokoro JV Management Ltd | Professional & scientific | 2022 |
| Kokoro Newbury Ltd | Hospitality | 2021 |
| Kokoro Peterborough Ltd | Hospitality | 2022 |
| Kokoro Poole Ltd | Hospitality | 2022 |
| Kokoro Southampton Ltd | Hospitality | 2020 |
| Kokoro Trading Ltd | Wholesale & retail | 2015 |
| Kokoro Twickenham Ltd | Hospitality | 2019 |
| Kokoro Urban Ltd | Hospitality | 2020 |
| Kokoro Weybridge Ltd | Hospitality | 2021 |
| Kokoro Worthing Ltd | Hospitality | 2024 |
| Komfaus Limited | Real estate | 2019 |
| Koniu Construction Ltd | Professional & scientific | 2019 |
| Konnect Education Limited | Education | 2023 |
| Kother Nutrition Limited | Health & social care | 2026 |
| Kottage Ltd | Real estate | 2019 |
| KP Platinum Cars Ltd | Wholesale & retail | 2023 |
| KRA POW Festivals Ltd | Hospitality | 2021 |
| KRA POW Markets Ltd | Hospitality | 2021 |
| KRM CAD Limited | Construction | 2026 |
| Ksai Consulting Limited | Professional & scientific | 2018 |
| Ksbi Ltd | Health & social care | 2021 |
| KT Oriental Chef Limited | Hospitality | 2025 |
| Kulbis Engineering Ltd | Construction | 2018 |
| Küta Studio Ltd | Other services | 2025 |
| L Mehta Consultants Limited | Professional & scientific | 2016 |
| L P Management (London) Ltd | Households | 2018 |
| L&A Consulting Limited | Professional & scientific | 2020 |
| L&A Property Holdings Ltd | Real estate | 2022 |
| L.E.D Developments Ltd | Construction | 2023 |
| L7 Cyber Consulting Ltd | Information & communication | 2026 |
| LA Lune Noire Ltd | Wholesale & retail | 2017 |
| Lacey Hound Medicare Limited | Health & social care | 2015 |
| Laclasse London Ltd | Other services | 2021 |
| LAD Trade Ltd | Wholesale & retail | 2025 |
| Ladies Decorating Services Limited | Construction | 2012 |
| Lake View Events Ltd | Agriculture & fishing | 2009 |
| Lakeside Sauna Co Ltd | Administrative & support | 2025 |
| Lamar Financial Service Limited | Financial services | 2019 |
| Lamport Newton Ltd | Information & communication | 2025 |
| Lanaegan Investments Ltd | Financial services | 2025 |
| Landmark London Developments Limited | Real estate | 2016 |
| Lantic Bay Limited | Financial services | 2021 |
| Lara Capital Limited | Administrative & support | 2025 |
| Laura Hollins Consultancy Limited | Professional & scientific | 2023 |
| Laura Wiggins Property Limited | Real estate | 2024 |
| Lawham Limited | Construction | 2019 |
| Lawrence William Morley Ltd | Real estate | 2019 |
| Lazpro Property Services Ltd | Construction | 2026 |
| Lazy YAK GM Ltd | Administrative & support | 2022 |
| Lazy YAK Investments Ltd | Professional & scientific | 2020 |
| LC Equestrian Services Ltd | Agriculture & fishing | 2023 |
| LC Michaels Ltd | Wholesale & retail | 2023 |
| LCT Pensions Limited | Financial services | 1988 |
| LCV Services Ltd | Construction | 2023 |
| Leaman Crellin Limited | Professional & scientific | 2018 |
| Lecs (Surrey) Ltd | Construction | 2025 |