| Interactive Pages Ltd | Cambridgeshire |
| Interactive Software Ltd | West Midlands |
| Interactive Solutions | West Yorkshire |
| Interactive Systems Solutions Ltd | Surrey |
| Intercai Mondiale | Berkshire |
| Intercede | |
| Intercity Technology Ltd | West Midlands |
| Intercole Sub-Contract Services Ltd | Hampshire |
| Interconics Ltd | Wiltshire |
| Interconnect Direct Ltd | Bristol |
| Interconnect IT Ltd | Merseyside |
| Interdirect | Buckinghamshire |
| Interdisciplinary Computing and Complex BioSystems | |
| Interface Developers | Worcestershire |
| Interface Financial Planning Ltd | |
| Interface2 Ltd | East Sussex |
| Intergage Ltd | Dorset |
| Interhost | Kent |
| InterlockDigital Ltd | |
| Intermedia Group Ltd | |
| International Centre for Mathematical Sciences | Edinburgh |
| International Computer Systems (London) Ltd | Greater London |
| International Copiers | Berkshire |
| International POS Ltd | Lancashire |
| International Security Expo | |
| International Software Publishing Ltd | Hampshire |
| International Union for Physicial and Engineering Sciences in Medicine | |
| International Workplace Group plc | |
| Internative Software Ltd | |
| Internet Assist Ltd | Essex |
| Internet Computer Bureau Ltd | Greater London |
| Internet Consultants and Associates Ltd | Hampshire |
| Internet Creation Ltd | Fife |
| Internet Ideas Ltd | |
| Internet Mate Ltd | |
| Internet Sales Drive | |
| Internet Solutions Services Ltd | Greater Manchester |
| Internet Videocommunications | Buckinghamshire |
| Internet-Ink | |
| Internet-ink.com | Nottinghamshire |
| InternetNow | Cambridgeshire |
| Internetology | Wrexham County Borough |
| Internetware Group Ltd | |
| Internwise | |
| Interphase | |
| Interrodata Ltd | |
| Intersite Technologies Ltd | Hertfordshire |
| Intersoft Systems & Programming Ltd | |
| Intertek Group plc | |
| Interverse Studios | |