| Oser Limited | Wholesale & retail | 2010 |
| Osho Motors UK Ltd | Wholesale & retail | 2025 |
| Ostlers Court Residents Limited | Real estate | 1989 |
| Otella Studios Ltd | Professional & scientific | 2020 |
| Otermans INS EDU Ltd | Information & communication | 2020 |
| Oulofa Limited | Wholesale & retail | 2019 |
| OUR Builder London Limited | Construction | 2009 |
| Ouro Medicines Ltd | Professional & scientific | 2024 |
| Outlook Fostering Services Limited | Health & social care | 2002 |
| Outsource Worldwide Limited | Wholesale & retail | 2026 |
| Overview Homes Limited | Real estate | 2025 |
| Owen Coyle Managements Limited | Construction | 1969 |
| Owen Enforcement Limited | Other services | 2018 |
| Owen GAS Ltd | Manufacturing | 2015 |
| OWL Cleaning Services Ltd | Administrative & support | 2016 |
| Owncars Limited | Wholesale & retail | 2020 |
| OX Property Ltd | Real estate | 2011 |
| Oxara Construction Ltd | Construction | 2025 |
| Oxford Knowledge Village Limited | Information & communication | 2013 |
| Oxlet House (Ampthill) Management Company Limited | Households | 2011 |
| Oxular Acquisitions Limited | Professional & scientific | 2020 |
| Oxular Limited | Professional & scientific | 2014 |
| Oypla.Com LLP | | 2012 |
| OZ London Ltd | Hospitality | 2012 |
| OZI Mailing Ltd | Transport & logistics | 2015 |
| Ozmium Limited | Health & social care | 2025 |
| Ozone Contracts Limited | Professional & scientific | 2017 |
| P Conlon Consulting Limited | Professional & scientific | 2014 |
| P Hiseman Tech Ltd | Professional & scientific | 2024 |
| P J Gallagher Garden Services Ltd | Administrative & support | 2026 |
| P K B Therapy Limited | Health & social care | 2020 |
| P R Power Services Ltd | Construction | 2025 |
| P T Design & Build Limited | Construction | 2014 |
| P Timms Ltd | Construction | 2014 |
| P Turnbull Limited | Professional & scientific | 2008 |
| P&D Building Solution Ltd | Construction | 2025 |
| P&G Premier Improvements Ltd | Construction | 2019 |
| P&S Living Limited | Real estate | 2025 |
| P.R.M.C. Limited | Households | 1989 |
| Pace-E-Solutions Limited | Information & communication | 2002 |
| Paddington Central Hotel Ltd | Hospitality | 2019 |
| Padel Anywhere Limited | Wholesale & retail | 2024 |
| Pagop Ltd | Transport & logistics | 2019 |
| Pagp Healthcare Ltd | Health & social care | 2015 |
| Pahelwan Group Limited | Hospitality | 2026 |
| Pahelwan Immigration London Limited | Administrative & support | 2026 |
| Paintballing Limited | Arts & recreation | 2010 |
| Paishang Biotechnology Ltd | Professional & scientific | 2023 |
| PAK Holdings Ltd | Extraterritorial | 2026 |
| Pakanna Ltd | Professional & scientific | 2009 |
| Palace Mews Management Company Limited | Households | 1986 |
| Pali Estates UK Limited | Real estate | 2020 |
| Palladium Design Studio Ltd | Professional & scientific | 2025 |
| Pallav Properties and Development Ltd | Households | 2024 |
| Palm Care Limited | Health & social care | 2000 |
| Palra Properties Ltd | Real estate | 2020 |
| Pampered Pups Ltd | Other services | 2025 |
| PAN London Properties Limited | Real estate | 2020 |
| Panam Executive Cars Limited | Transport & logistics | 2000 |
| Panda & Associates Limited | Professional & scientific | 2022 |
| Pandora London (PVT) Ltd. | Administrative & support | 2018 |
| Panentheism Limited | Extraterritorial | 2010 |
| Panther Marketing Limited | Hospitality | 2008 |
| Panthera Group Limited | Construction | 2005 |
| Panthera Security Limited | Construction | 2008 |
| Panthera Temporary Site Services Limited | Construction | 2023 |
| Papaz Peri Peri Pizza & Burgers Ltd | Hospitality | 2018 |
| Papetme Limited | Health & social care | 2010 |
| Papota UK Limited | Construction | 2026 |
| Paradigm Professional Services Ltd | Professional & scientific | 2016 |
| Paradise Catering Services Ltd | Hospitality | 2022 |
| Paradise Road Ltd | Real estate | 2024 |
| Paralegal Eagles Ltd. | Professional & scientific | 2015 |
| Paramount Care Homes Ltd | Health & social care | 2025 |
| Paramount Commercial Finance Limited | Financial services | 2016 |
| Paramount Housing Group Ltd | Real estate | 2020 |
| Paras 2000 Limited | Information & communication | 1996 |
| Paras Global Limited | Wholesale & retail | 2014 |
| Parfums Aurelian Nocturne Limited | Wholesale & retail | 2025 |
| Pargaas Estate Ltd | Real estate | 2024 |
| Pari Traders Ltd | Wholesale & retail | 2020 |
| Park Direct UK Limited | Administrative & support | 2010 |
| Park Foster Care Ltd | Health & social care | 2003 |
| Park House Management (High Wycombe) Company Ltd | Administrative & support | 2019 |
| Park View Resident's Management (Hitchin) Limited | Households | 2025 |
| Park Way Enfield Ltd | Real estate | 2026 |
| Park Wood Court Management Limited | Households | 2012 |
| Parkcroft Developments (Old School}Limited | Real estate | 2005 |
| Parkhouse Resi Limited | Households | 2023 |
| Parksons UK Limited | Wholesale & retail | 2001 |
| Parkview House Investments Limited | Real estate | 2024 |
| Parkway Connect Ltd | Transport & logistics | 2025 |
| Parmar Ventures Homes Limited | Real estate | 2019 |
| Parmar Ventures Ltd | Construction | 2001 |
| Parris Brows Ltd | Other services | 2025 |
| Parse Medical Limited | Professional & scientific | 2024 |
| Partnership Aviation | | 1990 |
| Pasquale Vacirca Consulting Limited | Construction | 2012 |
| Passion Solutions Ltd | Construction | 2019 |
| Passman Leonard Associates Limited | Professional & scientific | 2010 |