| Cheap Web Design | Surrey |
| Check It Out | |
| Checkbot | |
| Checkd Group | |
| CheckMySystems Ltd | |
| Checkout.com | Greater London |
| Checkstep | |
| Cheeky Communications Ltd | Kent |
| Cheeky Munkey IT Support | Hertfordshire |
| Cheerfy Ltd | |
| Cheil UK | |
| Chelmer Web Design | Essex |
| Chelsea Apps | |
| Chelsoft Club Membership Software | Gloucestershire |
| Cheltenham Computer Repairs | Gloucestershire |
| Cheltenham Computer Specialists | Gloucestershire |
| Chembiotech Laboratories | |
| Chemical Design | |
| Chemify | |
| ChemOvation Ltd | |
| Chemring Group plc | |
| ChemSoft Ltd | Cheshire |
| Cheqd | |
| Chersoft Ltd | |
| Cheshire Cat Marketing Ltd | |
| Cheshire Datasystems Ltd | Greater Manchester |
| Chess Digital Ltd | Renfrewshire |
| Chess ICT | Oxfordshire |
| Chess Logistics Technology Ltd | |
| Chester Marketing Solutions Ltd | |
| Chesterton Software Development Ltd | |
| ChestPal Pro | |
| Chestysoft | North Yorkshire |
| Cheviot Data Systems | |
| Chiaro Technology Ltd | |
| Chichester Website Design | |
| Chick Digital | |
| Chicsystems | Norfolk |
| Chill Web Designs | |
| Chillblast | Dorset |
| Chillfire Ltd | Surrey |
| Chilliapple Ltd | |
| Chillibyte | |
| Chiltern Telecom Ltd | |
| Chilternmac | Cornwall |
| Chilton Computing | |
| Chimp Digital | |
| Chimpare | |
| Chinkin Design | Norfolk |
| Chip Financial Ltd | Greater London |