| Propellernet | |
| Propelr Agency Ltd | |
| Proper Marketing Group Ltd | |
| Property Partner | |
| Property Portfolio Software | Cheshire |
| Property Web Design Pro Ltd | Shropshire |
| Property Webmasters | |
| propertyLab Ltd | Nottinghamshire |
| Proporta Ltd | East Sussex |
| Proportunity Ltd | |
| ProPraxis Ltd | Leicestershire |
| ProPrivacy | |
| ProQuo AI | |
| ProReal Ltd | |
| ProSapient | |
| Prosody IM | Worcestershire |
| Prosopo | |
| prosource.it Ltd | Aberdeen |
| Prospatek Ltd | Lancashire |
| Prospec Systems Ltd | |
| Prospect Solutions Ltd | |
| Prospective Labs Ltd | |
| ProspectSoft | Buckinghamshire |
| Prosper | |
| Prosys Computing Ltd | |
| Prosys Development Services | Surrey |
| Protean Inbound | Berkshire |
| Protean Software | |
| Protec IT Solutions Ltd | Berkshire |
| Protec Technical Ltd | |
| ProTech Computer Systems Ltd | West Midlands |
| ProTechLabs | |
| Protechmedia | |
| ProtectBox | |
| ProteinLogic Ltd | |
| ProTel (Professional Telecoms) Solutions Ltd | Isle of Wight |
| Proteome Sciences plc | |
| Proteotype Diagnostics | |
| Prothea Technologies Ltd | |
| Proto Software | |
| Protocol Ltd | Surrey |
| Protologic | South Yorkshire |
| ProtonDx Ltd | |
| Prototype Creative | South Yorkshire |
| Protouch | West Yorkshire |
| ProTrainings Europe Ltd | |
| Protronix EMS Ltd | Bedfordshire |
| Provar Ltd | |
| Proveca Ltd | |
| Proven Web | |