| Printed Wiring Technologies Ltd | Hertfordshire |
| Printer Consumbales Supplies Ltd | Northamptonshire |
| Printerbase Ltd | Greater Manchester |
| Printercare | Surrey |
| Printerland Ltd | Greater Manchester |
| Printoia Web Design | |
| PrintUK.com | |
| Printware | |
| Prior Analytics Ltd | Greater London |
| Priorclave Ltd | |
| Priority IT Solutions Ltd | Wiltshire |
| Priority Pixels (Holdings) Ltd | |
| Priory Web Services | Edinburgh |
| Prism | Cheshire |
| Prism Digital Ltd | |
| Prism Electronics Ltd | Cambridgeshire |
| Prism Software (GB) Ltd | |
| Pristine Media UK | |
| Privacy Experience Agency | |
| PrivacyCloud | |
| Privasee Group Ltd | |
| Private Equity Wire | |
| Private Practice Software | Staffordshire |
| Priviledged Software Ltd | |
| Privitar Ltd | |
| Pro Digital Marketing | |
| Pro IT City Ltd | |
| Pro Logic Computers (UK) Ltd | West Yorkshire |
| Pro Software Company | |
| Pro Web Design | |
| Pro-Sapien Software | |
| pro-Solve International Ltd | Buckinghamshire |
| ProAct International Ltd | Denbighshire |
| Proactis Holdings plc | West Yorkshire |
| ProAcumen Ltd | Oxfordshire |
| ProAxsis | |
| Probe Test Solutions Ltd | |
| Probitas Enterprise Solutions Ltd | Northamptonshire |
| ProcessFlows UK Ltd | Hampshire |
| ProClinical Consulting | |
| ProCo IT | Somerset |
| Procosoft Ltd | |
| Procreation UK Ltd | Surrey |
| Procure Ai | |
| Procurement Leaders Ltd | |
| Procyon Ltd | Northamptonshire |
| PRODA Ltd | |
| Prodec Networks | Berkshire |
| Prodo | Cheshire |
| ProdPad | |