| Poseidon Aquatic Resource Management Ltd. | Addlestone | 2001 |
| Poseidon Fishing Limited | Peterhead | 2018 |
| Poseidon Services Limited | London | 1986 |
| Poseidon Trawlers Limited | Brixham | 2020 |
| Posh Dogz Boarding Ltd | Liverpool | 2024 |
| Posh Paddocks Limited | Thirsk | 2005 |
| Posh Paws Fertility Clinic Ltd | Ringwood | 2023 |
| Posh Poos Ltd | Eastleigh | 2019 |
| Posh Pups Dog Grooming Ltd | Bradford | 2020 |
| Poshdogz Limited | Lincoln | 2015 |
| Posherdors Ltd | London | 2025 |
| Positive Approach Canine Coaching Ltd | Bridge Of Weir | 2025 |
| Positive Movement Equine Therapy Ltd | Wolverhampton | 2024 |
| Positive Potions Limited | Anglesey | 2017 |
| Post Green Services Limited | Dorchester | 2014 |
| Postwick Hall Farm Limited | Norwich | 2016 |
| POT and Plant Ltd | London | 2026 |
| Potager Garden Limited | Falmouth | 2008 |
| Potash Development Association | York | 1985 |
| Potash Farm Limited | Woodbridge | 2020 |
| Potash Farm Services Limited | Bury St. Edmunds | 2014 |
| Potash Farming Ltd | Bury St Edmunds | 2022 |
| Potash Nursery Limited | Stowmarket | 2017 |
| Potato Agritech Ltd | Spalding | 2026 |
| Potato Agronomy and Technology Limited | Halstead | 2025 |
| Potato Partners (NI) Limited | Newry | 2002 |
| Potato Storage Insight Limited | Spalding | 2021 |
| Potato Storage Treatments Limited | Spalding | 2003 |
| POTS4PLOTS Ltd | Newbury | 2022 |
| Potsford Farm Ltd | Woodbridge | 2010 |
| Pottahey Ltd | Stockport | 2026 |
| Potter Oyler Limited | Lynsted | 1923 |
| Potterne Eggs Ltd | Leamington Spa | 2025 |
| Potters Poultry International Limited | Coventry | 1983 |
| Potters Poultry Limited | Coventry | 2020 |
| Potters Trading Ltd | Wimborne | 2025 |
| Potticks Pigs Limited | Bath | 1979 |
| Potting Shed Ventures Limited | Coleraine | 2024 |
| Pottles Premier Plants Ltd | Holywell | 2002 |
| Potty Little Plants Ltd | Newtownabbey | 2024 |
| Poulton Pets Ltd | Blackpool | 2015 |
| Poultrade Ltd | Glasgow | 2022 |
| Poultries AL Hilal Limited | Manchester | 1978 |
| Poultry Catchers Ltd | Doncaster | 2005 |
| Poultry Cleaning Services Ltd | Hereford | 2025 |
| Poultry Farming Ltd | Great Chesterford | 2022 |
| Poultry Handling Solutions Limited | Norwich | 2010 |
| Poultry Pros Limited | Borehamwood | 2022 |
| Poultry Wizard Limited | Barnsley | 2014 |
| Poultrysolve Ltd | Much Wenlock | 2008 |
| Pound Farm Limited | Pontypridd | 2022 |
| Pour the Milk Limited | Sandbach | 2020 |
| Pouton Farms Ltd | Belfast | 1999 |
| Pouton Limited | Newton Stewart | 2020 |
| Powell Farming Ltd | Shrewsbury | 2021 |
| Powell Forestry Limited | Hook | 2018 |
| Powell Sheepdogs Limited | Shrewsbury | 2018 |
| Power AXE Engineering Ltd | Port Glasgow | 2022 |
| Powerarb Ltd | Tillicoultry | 2016 |
| Powerarb Utility Contractors Limited | Portree | 2022 |
| Powerdrama Limited | Sawbridgeworth | 2003 |
| Powerline and Tree Services Ltd | Leominster | 2008 |
| Powerline Services (MLJ) Limited | Leominster | 2006 |
| Powerwash (Cheddar) Limited | Bridgwater | 2004 |
| Powis Castle Shoot Limited | Welshpool | 2013 |
| Poynton Ltd. | Malmesbury | 2000 |
| Poyston Farm Limited | Crymych | 2003 |
| PP Groundcare Limited | Bedford | 2011 |
| PPG (Scotland) Ltd | Bonnybridge | 2022 |
| PPP Regulatory Consulting Ltd | Market Rasen | 2025 |
| PPW Farms Ltd | Dungannon | 2012 |
| PQ Dog Day Care Limited | Chelmsford | 2021 |
| PR Falcons Limited | Bradford | 2016 |
| PR Trees Ltd | London | 2026 |
| Practical Agronomy Ltd | Hull | 2025 |
| Practical Dairy Solutions Limited | Cumnock | 2014 |
| Practicality Brown Limited | Buckinghamshire | 1987 |
| Praedlands Limited | Epsom | 1961 |
| Prag Limited | Pembrokeshire | 2002 |
| Prag Solutions Ltd | London | 2025 |
| Prakrith Ltd | London | 2019 |
| Prathista BIO Tech Limited | Amersham | 2022 |
| Praxis Land Management Limited | Monmouth | 2020 |
| PRB Farming Limited | Chesterfield | 2026 |
| PRE Formed Limited | Durham | 2021 |
| Precious Bull Ltd | Hullbridge | 2022 |
| Precious Paws (Suffolk) Ltd | Ipswich | 2024 |
| Precious Paws Day Care and Home Boarding Limited | Castleford | 2025 |
| Precious Paws Ingleby Ltd | Stockton-On-Tees | 2024 |
| Precious Paws Premium Doggy Day Care + Ltd | Liverpool | 2019 |
| Preciousbear Frenchies Limited | Liverpool | 2018 |
| Preciousdax Ltd | Peterborough | 2024 |
| Precise Crop Nutrition Limited | Stamford | 2011 |
| Precision Agriculture Africa Ltd | Wimborne | 2023 |
| Precision Agronomy Ltd | Ely | 2010 |
| Precision Bars Limited | Halesowen | 2006 |
| Precision Deer Management UK Ltd | Crowthorne | 2025 |
| Precision Drone Services Ltd | Selby | 2024 |
| Precision Landcare Ltd | Swansea | 2012 |
| Precision Outdoors Ltd | London | 2026 |