C
- C.K
- CableQuick
- Calex
- Capital Valley Plastics Ltd
- Carlisle Brass
- CarPlan
- Carroll and Meynell Transformers
- Carron Phoenix
- Carysil
- CAT
- CED
- Charles Bentley
- Cherry Blossom
- Cisa
- City Knights
- CK Magma
- Coba
- Cobra
- Codelocks
- Collingwood
- Colorfill
- Colours
- Command
- Conex Banninger B Press
- Conex Banninger B Press Gas
- Contactum
- Cooke and Lewis
- Cookerflex
- Corefix
- Crabtree
- Cramer
- Creda
- Cromar
- Croydex
- Culina
- Cuprinol
- Curtis Dyna-Fog