| inspHire Ltd | |
| Inspira Digital Ltd | |
| Inspiralis Ltd | |
| Inspirar Business Support Ltd | |
| Inspiratech 2000 Ltd | |
| Inspire | Hertfordshire |
| Inspire Infosol UK Ltd | Greater London |
| Inspire IT Services | Perth and Kinross |
| Inspired Agency | |
| Inspired Energy | |
| Inspired Minds Media Ltd | |
| Inspired Recruitment | Greater Manchester |
| instaCommerce Ltd | Derbyshire |
| InstaDeep Ltd | |
| Installing IT | Cheshire |
| Instanda | |
| InStandart | |
| Instant365 | |
| Instantcart | |
| Instantprint | |
| Instem Group of Companies | Staffordshire |
| Instil Software | |
| Instil Software Ltd | Belfast |
| Instill.AI Ltd | |
| Institute and Faculty of Actuaries | |
| Institute for Fiscal Studies | |
| Institute of Cancer Research | |
| Institute of Development Studies | |
| Institute of Food Science and Technology | |
| Institute of Mathematics and its Applications | Essex |
| Institute of Spring Technology | |
| Instrom Ltd | Buckinghamshire |
| Instrument Repair Service | Nottinghamshire |
| Insurami | |
| Insurance & Mobility Solutions | |
| Insure Apps Ltd | |
| Insurtech Gateway | |
| Insurtech Insights | |
| Inta People Ltd | Cardiff |
| IntaForensics Ltd | Warwickshire |
| Intandem Communications | |
| IntaRide Ltd | Worcestershire |
| Intasoft Ltd | Devon |
| Intec Systems (Blackburn) Ltd | |
| Intec Systems Ltd | Hampshire |
| Intechnia Ltd | Wiltshire |
| InTechnology plc | |
| IntechOpen Ltd | |
| Integer Micro Systems Ltd | Essex |
| Integral Communications | Staffordshire |