| Nupharm Limited | Wholesale & retail | 2003 |
| Nviron Group Ltd | Information & communication | 2017 |
| Nviron Limited | Information & communication | 1988 |
| NW Tiles Ltd | Construction | 2026 |
| Nwrs Holdings Limited | Professional & scientific | 2020 |
| Nxsole Ltd | Professional & scientific | 2026 |
| O'Hare Limited | Extraterritorial | 2020 |
| O'Neill Signs Limited | Manufacturing | 2008 |
| Oasis Business Solutions Limited | Information & communication | 2010 |
| Ocean Revival Adventures Ltd | Arts & recreation | 2025 |
| Oceanflyer Medical Ltd | Administrative & support | 2023 |
| Octapharm Limited | Wholesale & retail | 1983 |
| Octopus Project Engineering Limited | Professional & scientific | 2011 |
| OFF Centre Records Ltd. | Arts & recreation | 2017 |
| Ohmyglitter Ltd | Manufacturing | 2017 |
| Okel Group Ltd | Financial services | 2022 |
| Old Chapel Properties Ltd | Real estate | 2023 |
| Old Town OFF License Ltd | Wholesale & retail | 2026 |
| Olive Tree Catering UK Cafes and Bars Limited | Hospitality | 2024 |
| Olive Tree Catering UK Limited | Hospitality | 2013 |
| Omniroot Limited | Extraterritorial | 2013 |
| Oncodrug Ltd | Professional & scientific | 2021 |
| One Mgmt Limited | Professional & scientific | 2013 |
| One of a Kind Events Limited | Other services | 2021 |
| One Stop Inspector Limited | Water & waste | 2016 |
| One Stop MCR Limited | Wholesale & retail | 2026 |
| Only for One Ltd | Transport & logistics | 2020 |
| Onlytans Runcorn Ltd | Other services | 2025 |
| Oomph Learning and Development Ltd | Professional & scientific | 2019 |
| Open 360 | Education | 2012 |
| Operational (UK) Limited | Professional & scientific | 1991 |
| Operational Group Limited | Professional & scientific | 2005 |
| Optima Digital Solutions Ltd | Information & communication | 2021 |
| Optimum Integrated Solutions Limited | Construction | 2025 |
| Optimum Networks Ltd | Information & communication | 2025 |
| Orbital Software Solutions Ltd | Information & communication | 2017 |
| Organise Limited | Information & communication | 2006 |
| Orlando Villa Rentals Ltd | Hospitality | 2014 |
| OUR House Solutions Ltd | Construction | 2022 |
| Ourvita Beauty UK Limited | Manufacturing | 1978 |
| Ourvita Health & Beauty Solutions Limited | Manufacturing | 1994 |
| Ourvita Health & Beauty Solutions US Limited | Financial services | 2019 |
| Ourvita Healthcare UK Limited | Financial services | 1985 |
| Ourvita Nutraceuticals Limited | Professional & scientific | 1979 |
| Ourvita Nutraceuticals Processing Limited | Manufacturing | 1984 |
| Outside-In Consulting Limited | Professional & scientific | 2008 |
| Owens Electrical Limited | Professional & scientific | 2015 |
| Oxhoo UK Limited | Wholesale & retail | 2015 |
| Oxton Civil Solutions Ltd | Construction | 2020 |
| P Laing Limited | Real estate | 2013 |
| P R Properties (Hull) Ltd | Real estate | 2025 |
| P S Transport Services Ltd | Transport & logistics | 2024 |
| P.D.R. Electrical Limited | Construction | 1989 |
| P.I.W. Narrowboat Services Ltd | Manufacturing | 2018 |
| P2S Construction Ltd | Construction | 2025 |
| Pa's 4 YOU Ltd | Health & social care | 2022 |
| Pacific Composites Europe Limited | Manufacturing | 1992 |
| Packed Chlorine Limited | Wholesale & retail | 2012 |
| Pagirys Ltd | Transport & logistics | 2018 |
| Paisley Property Limited | Construction | 2015 |
| Parallel Solutions Ltd | Professional & scientific | 2019 |
| Park View Garden Estate Ltd | Real estate | 2023 |
| Partner Tech UK Corp Limited | Wholesale & retail | 2008 |
| Past Explorers Ltd | Wholesale & retail | 2021 |
| Pasu Enterprise Ltd | Wholesale & retail | 2020 |
| Patrickokz Limited | Professional & scientific | 2019 |
| Paul Eugen Ltd | Transport & logistics | 2018 |
| Paul Roach Instrumentation & Control Limited | Administrative & support | 2007 |
| Paul Stanley Abacus Associates Ltd | Professional & scientific | 2023 |
| Paulptattoo Ltd | Arts & recreation | 2025 |
| Pc&Sonsconstruction Ltd | Construction | 2026 |
| Pckm Properties Limited | Real estate | 2023 |
| PDB Compliance Ltd | Financial services | 2012 |
| PDJ Consultants Limited | Professional & scientific | 2015 |
| Peacetrain Medical Limited | Health & social care | 2008 |
| Peak Influence Agency Ltd | Information & communication | 2025 |
| Peak Perfection Property Maintenance Ltd | Real estate | 2026 |
| Peak Solar and Electrical Services Limited | Construction | 2022 |
| Pearsons Packaging Ltd | Wholesale & retail | 2025 |
| Peerless Plastics Limited | Professional & scientific | 1963 |
| Penguin Adventures Limited | Professional & scientific | 2022 |
| Peninsula Health LLP | | 2007 |
| Penitus Motorsport Ltd | Professional & scientific | 2014 |
| Penketh Floor Coverings Limited | Wholesale & retail | 1982 |
| Penta Transport Limited | Transport & logistics | 2015 |
| Pentulo Limited | Information & communication | 2025 |
| Pereira Accounting and Consultancy Services Limited | Professional & scientific | 2022 |
| Perel Trans Limited | Transport & logistics | 2017 |
| Perform Personal Training Ltd | Arts & recreation | 2024 |
| Performance Farriery & Consultancy Ltd | Agriculture & fishing | 2017 |
| Perky Grinders Ltd | Hospitality | 2023 |
| Persona Skin Limited | Other services | 2024 |
| Personal Best Coaching Limited | Health & social care | 2021 |
| Personal Freedom Limited | Health & social care | 2022 |
| Petals Vintage Tea Shop Ltd | Hospitality | 2021 |
| Peter Allen Haulage Limited | Transport & logistics | 2011 |
| Peter Dale International (PDI) Limited | Transport & logistics | 2010 |
| Peter Green Transport Limited | Transport & logistics | 2009 |
| Peter Mccallum Transport Limited | Financial services | 2017 |
| Peter Naylor Limited | Professional & scientific | 2022 |