| Prodrive | |
| Product Guru | |
| Product Insight Ltd | Greater London |
| Product People Ltd | |
| Product Technology Partners Ltd | Cambridgeshire |
| ProFactor Software Ltd | Northamptonshire |
| Professional Computer Support Ltd | Greater Manchester |
| Professional Web Design in Kent | |
| Profile Technology Services Ltd | Hertfordshire |
| ProfileTree Web Design and Digital Marketing Ltd | |
| ProFinda | |
| Profitable Websites Ltd | West Sussex |
| Profitmaster Systems Ltd | Nottinghamshire |
| ProFix IT | Newry, Mourne and Down |
| Profusion plc | Essex |
| Prog Academy | |
| Programmer's Notepad | Berkshire |
| Progressive Audio Visual Ltd | Kent |
| Progressive Robot | |
| Prohibition PR | |
| ProImmune Ltd | |
| PROiT Ltd | Hampshire |
| Project Cosmic Ltd | Devon |
| PROJECT in a box | Oxfordshire |
| Project Opal Ltd | |
| Project People | Bristol |
| Project Provenance Ltd | Greater London |
| Project36 Ltd | |
| ProjectHouse | Worcestershire |
| Prokarium | |
| Prolateral Consulting Ltd | Bedfordshire |
| Proliant Server Store | East Sussex |
| Prolog | Suffolk |
| Prologic Data Management | Mid-Ulster |
| Promatix Biosciences Ltd | |
| Prominent Media Ltd | Buckinghamshire |
| ProMo-Cymru | Cardiff |
| Promodo | Lincolnshire |
| Prompt | |
| PromptBase | |
| Prontaprint London | |
| Pronto Creative | |
| Pronto Etech Services | |
| ProntoSSL | Nottinghamshire |
| ProntX | |
| ProofID | Greater Manchester |
| ProofSpace | |
| Propel Marketing & Design | |
| Propel Tech Ltd | |
| Propeller Communications | |