| Optimum Solutions Independent Financial Advisers Limited | Financial services | 2001 |
| OR Pubs Limited | Hospitality | 2018 |
| Orbital Distribution ( UK ) Limited | Transport & logistics | 2011 |
| Orbital Maintenance Services Ltd | Construction | 2019 |
| Orchard 2 Office Delivery Ltd | Wholesale & retail | 2020 |
| Orchard AB Limited | Administrative & support | 2015 |
| Originalworx Ltd | Information & communication | 2021 |
| Orion OIL Limited | Administrative & support | 2008 |
| Ormonde Property Group Ltd | Real estate | 2022 |
| Orwell Developments Limited | Administrative & support | 2016 |
| Oseman GAS Services Limited | Construction | 2024 |
| Osgood Blues Limited | Real estate | 2018 |
| Oshun Limited | Information & communication | 2005 |
| OUR Village CIC | Health & social care | 2025 |
| Outdoor Landscapes Ltd | Construction | 2025 |
| P Gallagher Estates Limited | Construction | 2020 |
| P. & J. Dust Extraction Limited | Manufacturing | 1980 |
| P.J.Book-Keeping Limited | Professional & scientific | 2002 |
| Pace Export (International) Ltd | Wholesale & retail | 2023 |
| Paddyrose Ltd | Wholesale & retail | 2019 |
| Paradisus Lettings & Management Ltd | Real estate | 2025 |
| Paradisus Ltd | Real estate | 2020 |
| Parfigroup UK Limited | Administrative & support | 2017 |
| Parima Paper Limited | Wholesale & retail | 2001 |
| Park Green Ranger Fitness Ltd | Health & social care | 2024 |
| Parker Sign & Print Limited | Manufacturing | 2025 |
| Parkers Gates & Fencing Ltd | Construction | 2021 |
| Parkside Security Limited | Financial services | 2024 |
| Passcc Limited | Professional & scientific | 2007 |
| Pathus Limited | Construction | 2015 |
| Patrick West Legal Ltd | Professional & scientific | 2018 |
| Paul Selman Holdings Ltd | Financial services | 2022 |
| Peacock Inspection Limited | Professional & scientific | 2018 |
| Peak MT Renewables Ltd | Construction | 2022 |
| Pebble POT Limited | Construction | 2018 |
| Pedunculate Limited | Manufacturing | 2010 |
| Pelican Resources Limited | Real estate | 1995 |
| Pentatech Ltd | Construction | 2009 |
| Pentatemp Limited | Construction | 2021 |
| Perpetuus Advanced Materials Limited | Financial services | 2013 |
| Perpetuus Energy Limited | Financial services | 2011 |
| Perpetuus Research & Development Limited | Professional & scientific | 2013 |
| Perpetuus Tidal Energy Centre Limited | Energy | 2013 |
| Personnel Health & Safety Consultants Limited | Administrative & support | 1990 |
| Peter Doorey Building & Landscaping Limited | Construction | 2003 |
| Peter MAY Surveying & Estimating Ltd | Professional & scientific | 2013 |
| Petty Little Things Ltd | Wholesale & retail | 2026 |
| Phaure & Hawkins Because YOU CAN C.I.C. | Financial services | 2024 |
| Phsc PLC | Professional & scientific | 2000 |
| Physical Finance Limited | Financial services | 2017 |
| PIA Trading Limited | Administrative & support | 1987 |
| Piece of Play Inspections Ltd | Education | 2025 |
| Pillar and Pace Ltd | Wholesale & retail | 2025 |
| Pimli Deliveries Limited | Transport & logistics | 2017 |
| Pineapple Global Ltd | Extraterritorial | 2024 |
| Pineapple Medical Products Limited | Wholesale & retail | 2025 |
| Pipes, Planes and Properties Limited | Professional & scientific | 2025 |
| PIZZADELLACASA1 Ltd | Hospitality | 2025 |
| PJ Project Management Consultancy Ltd | Administrative & support | 2019 |
| Plan B Properties Ltd | Real estate | 2025 |
| Plan-A-Software Ltd | Information & communication | 2021 |
| Planet Health Ltd | Wholesale & retail | 2022 |
| Platform Power Limited | Construction | 2025 |
| Plumb 4 Less Limited | Wholesale & retail | 2005 |
| Plumbmech Limited | Manufacturing | 2009 |
| Plumbusters Ltd | Construction | 2022 |
| Poppleway Ltd | Professional & scientific | 2012 |
| Port Traction Limited | Transport & logistics | 2007 |
| Porter Chauffeur Services Ltd | Transport & logistics | 2023 |
| Portfolio Services Management Ltd | Construction | 2026 |
| Powell Analytics Ltd | Information & communication | 2023 |
| Power Systems Engineering Limited | Energy | 2006 |
| Powerboat ALPHA1 Ltd | Education | 2023 |
| Powerglen Limited | Professional & scientific | 2016 |
| Prash Holdings Ltd | Health & social care | 2013 |
| Prash Property Ltd | Real estate | 2021 |
| PRE Pack Pool Limited | Financial services | 2015 |
| Precision Damp Limited | Arts & recreation | 2022 |
| Precision NDT Limited | Professional & scientific | 2025 |
| Pride Developments (South) Limited | Hospitality | 1996 |
| Prime Construction Ltd | Construction | 2018 |
| Primeline Roofing Ltd | Construction | 2025 |
| Primeplumbing Solutions Ltd | Construction | 2024 |
| Printair Supplies Limited | Wholesale & retail | 2000 |
| Priory Business Group Ltd | Wholesale & retail | 1998 |
| Priory Digital Limited | Professional & scientific | 2017 |
| Priory Direct Limited | Wholesale & retail | 2009 |
| Priory Elements Limited | Wholesale & retail | 2021 |
| Priory Fulfilment Limited | Wholesale & retail | 2008 |
| Priory Print Management Ltd | Wholesale & retail | 2008 |
| Priory Storage Ltd | Administrative & support | 2008 |
| Pro Equipped Ltd | Wholesale & retail | 2020 |
| Pro Intense Football Academy Ltd | Education | 2025 |
| Pro-K Engineering Limited | Manufacturing | 2025 |
| Probeck IT Ltd | Information & communication | 2021 |
| Prodan Driving Ltd | Transport & logistics | 2018 |
| Proex Plant Hire Limited | Construction | 2012 |
| Prograde Plumber Ltd | Construction | 2025 |
| Prolific Signs Ltd | Extraterritorial | 2016 |
| Property Management Portfolio Ltd | Real estate | 2010 |