Cadbury workers are voting on possible strike action over claims the confectionery giant has broken pay promises.

Cadbury had broken a long-standing deal struck with workers at Cadbury's plants in Bourneville, Chirk, Marlbrook and Somerdale by refusing to honour the final year of a three-year pay agreement, union Unite claimed.

Any strike action would hit supplies of Cadbury products, predicted Unite national officer Jennie Formby. "All the managers have to do is keep their promise to the workforce and production will not be disrupted," she added.