| Petalite | |
| Pete's Computers | |
| PeteFinnigan.com Ltd | North Yorkshire |
| Peter Smith Freelance Web Design | Lancashire |
| PetMedix | Cambridgeshire |
| Petroleum Experts Ltd | Edinburgh |
| Petsi Global Ltd | |
| Peyk | |
| PF Nexus | |
| ph9 Ltd | Derbyshire |
| Phaedrus Systems Ltd | Staffordshire |
| Phagenesis Ltd | |
| Phaim Pharma Ltd | |
| Phare Health | |
| Pharian Ltd | West Sussex |
| Pharmanovia | |
| Pharmaphorum Media Ltd | |
| Pharmaseal | |
| PharmEnable | |
| PharmEnable Therapeutics | |
| PHARMExcel | |
| Pharmidex | |
| Pharos Data Ltd | Berkshire |
| PharSafer Associates Ltd | |
| PharSafer Associates Ltd | |
| Phase One Electronics Ltd | Hampshire |
| Phasecraft | |
| Phastar | |
| PHB Networking | |
| PHD Computer Consultants Ltd | Cumbria |
| PHD Worldwide | |
| Pheno Therapeutics | |
| Phenomenists Internet Ltd | Dorset |
| Phenotypeca Ltd | |
| Pheon Therapeutics | |
| Phi-Medics | |
| Philex Electronic Ltd | Bedfordshire |
| Philippe Rixhon Associates Ltd | Greater London |
| Phindigital | |
| PHINXT Robotics | |
| Phoebus Software Ltd | |
| Phoenix Datacom Ltd | Buckinghamshire |
| Phoenix Digital | |
| Phoenix Digital | |
| Phoenix Digital Media Ltd | |
| Phoenix Electronics Distribution Ltd | South Lanarkshire |
| Phoenix Link UK Ltd | Kent |
| Phoenix Network Communications | Derbyshire |
| Phoenix Software | East Riding of Yorkshire |
| Phoenix Total Security | Greater London |