| Only Hers Ltd | Other services | 2018 |
| Onseason Limited | Information & communication | 2026 |
| Ophm-Ed Ltd | Education | 2022 |
| OPR Consulting Ltd | Professional & scientific | 2023 |
| Oratory of the Good Shepherd | Other services | 2008 |
| Orchard Developments (East Anglia) Limited | Construction | 1983 |
| Orchard Homes (East Anglia) Limited | Construction | 2005 |
| Osborn Homes (East Anglia) Limited | Construction | 2019 |
| Osborn Property Investments Limited | Real estate | 2015 |
| Osborne Automotive Ltd | Water & waste | 2026 |
| Osier Developments Ltd | Construction | 2022 |
| OWC Trades Ltd | Construction | 2018 |
| Oxfordshire Greentech Ltd | Administrative & support | 2019 |
| Oxlip Investments Ltd | Real estate | 2026 |
| OZ Distributions Ltd | Wholesale & retail | 2026 |
| P & B Courier Ltd | Transport & logistics | 2025 |
| P & N Residential (EA) Limited | Real estate | 2018 |
| P C S (Welding) Limited | Wholesale & retail | 2004 |
| P W Mcdonald Ltd. | Transport & logistics | 2002 |
| P&N Residential LLP | | 2009 |
| P.E.S. Technologies Limited | Manufacturing | 2017 |
| P.H.I. (Kitchens & Bathrooms) Limited | Construction | 2007 |
| P.L. Ellis & SON Limited | Agriculture & fishing | 1965 |
| Pace Racing Developments Limited | Manufacturing | 1984 |
| Paint Your Plastics Limited | Manufacturing | 2010 |
| Palgrave (Kings Meadow) Management Company Limited | Administrative & support | 2004 |
| Palgrave Property Ltd | Hospitality | 2020 |
| Panos Transport Limited | Transport & logistics | 2019 |
| Paper Plane Communications Ltd | Professional & scientific | 2008 |
| Park Farm Holidays Ltd | Hospitality | 2023 |
| Park Radio Ltd | Information & communication | 2009 |
| Parkington Way Management Limited | Households | 2018 |
| Parkor Traders Limited | Wholesale & retail | 2016 |
| Paul Bacon Limited | Administrative & support | 2012 |
| Paul Durrant & SON (Builders) Ltd | Construction | 2003 |
| Paul Sasada Consulting Ltd | Administrative & support | 2017 |
| Paulandgail Limited | Manufacturing | 2020 |
| PDC Logistic Services Ltd | Transport & logistics | 2020 |
| Peddars Farms Limited | Agriculture & fishing | 2004 |
| Peddars Holdings Limited | Financial services | 2017 |
| Peddars Milling Limited | Manufacturing | 2022 |
| Peddars Properties Ltd | Real estate | 2020 |
| Peddars Veterinary Services Limited | Professional & scientific | 2018 |
| Pedz Photography Ltd | Professional & scientific | 2019 |
| Pegasus Motorsport Limited | Arts & recreation | 2025 |
| Pegasus Personnel Consultancy Limited | Professional & scientific | 2005 |
| Penev Service Limited | Wholesale & retail | 2023 |
| Pennoyers Ltd | Arts & recreation | 2010 |
| People in Construction Ltd | Administrative & support | 2008 |
| Pesra Solutions Limited | Transport & logistics | 2011 |
| Pet Doctors Limited | Professional & scientific | 1999 |
| Pet Emergency Treatment Services Limited | Professional & scientific | 1998 |
| Pet Vaccination Clinic Limited | Professional & scientific | 1996 |
| Pet Vaccination UK Limited | Professional & scientific | 2005 |
| Peter Haynes Associates (Safety & Operations) Ltd | Professional & scientific | 2010 |
| Peter Lewis Associates Limited | Professional & scientific | 1997 |
| Petersfield Plant Hire Ltd | Construction | 2004 |
| Pets Holding Limited | Professional & scientific | 2018 |
| PH & JE Murray Limited | Agriculture & fishing | 2025 |
| Philip Wing Landscaping Limited | Administrative & support | 2008 |
| Philippa Horn Limited | Information & communication | 2024 |
| Phoenix Recruitment Services Ltd | Administrative & support | 2022 |
| Pink HEN Limited | Financial services | 2023 |
| PIP Projects Ltd | Construction | 2025 |
| Pitch Perfect Properties Limited | Real estate | 2025 |
| Pitcher Brothers Limited | Agriculture & fishing | 2013 |
| Pitt Farm Developments Ltd | Construction | 2023 |
| Pixelwood Ltd | Information & communication | 2014 |
| PJ Machinery Limited | Administrative & support | 2002 |
| Place Farm Shop Limited | Wholesale & retail | 2016 |
| Plain Press Limited | Information & communication | 2016 |
| Planetal Limited | Professional & scientific | 2022 |
| Planetal Properties Ltd | Real estate | 2024 |
| Platinum Accountancy Limited | Professional & scientific | 2003 |
| PLS Financial Services Limited | Financial services | 2008 |
| Podthings Ltd | Health & social care | 2012 |
| Polished Pro Limited | Extraterritorial | 2019 |
| Poplar Farm (Norfolk) Ltd | Agriculture & fishing | 2022 |
| Poppi (Holdings) Ltd. | Extraterritorial | 2015 |
| Poppi Group Commercial Ltd | Extraterritorial | 2020 |
| Poppi Investments Ltd | Real estate | 2013 |
| Poppi Limited | Financial services | 2013 |
| Poppi Management Ltd | Professional & scientific | 2013 |
| Poppi Projects Limited | Construction | 2005 |
| Poppi Residential Ltd | Real estate | 2013 |
| Positive Earth Limited | Construction | 2009 |
| Positive Lighting Holdings Ltd | Financial services | 2016 |
| Positive Lighting Solutions Ltd | Wholesale & retail | 2006 |
| Potencia Engineering Limited | Professional & scientific | 2014 |
| Practical Ecology Limited | Professional & scientific | 2010 |
| Practical Plants Ltd | Wholesale & retail | 2015 |
| Precision Histology International Limited | Professional & scientific | 1987 |
| Precision Pilots Association Limited(The) | Arts & recreation | 1980 |
| Precision Plumbing (EA) Limited | Construction | 2017 |
| Preservation Equipment Limited | Administrative & support | 1988 |
| Preservation in Action Limited | Wholesale & retail | 1985 |
| Pretty Engineering Limited | Extraterritorial | 2003 |
| Primary Patient Access Ltd | Professional & scientific | 2025 |
| Pro AV Supply Ltd | Construction | 2026 |
| Professional Lawn Services Ltd | Administrative & support | 2022 |