The Midlands processing plants receives birds cutting and packing from 2 Sisters primary sites in Lincolnshire, Norfolk, Devon and Scotland. The company currently processes about three million birds a week.

The union says that if Unite members vote to strike it would jeopardise the supply of poultry products to all of the major supermarket suppliers, and inevitably hit supermarket shelves.

Unite added that 2 Sisters has proposed an offer of £214 per week.

This is just eight pence an hour above the minimum wage for staff, who work a 37.5 hour week usually on unsociable hours, split between morning and afternoon shifts, the union said.

Unite said it was a shocking level of payment proposed by the company, which does not reflect the hard work the staff put in.

However, a company spokesman said that the union claim is incorrect and he added, "We currently pay a premium above the national adult minimum wage and our compromise offer would continue to pay the existing premium to the lowest earners."

Negotiations began in June but, the union claims, the company has not yet disclosed any financial figures to assist the negotiations.

Joe Clarke, Unite regional industrial organiser, said, "We have been forced into this action which will hit supermarket shelves and a Sunday lunch favourite. This is not our preferred choice of route to resolve this outstanding pay dispute and beat poverty pay.

"Our members work long, highly unsociable hours which hits their family life hard. Our members keep the supermarket chains producing good quality food and are only asking for a living wage in return. In the face of the company's derisory offer, we have no option but to ballot our members for industrial action and win them fair pay."

The 2 Sisters spokesman said, "We have shared the financial implications of the sudden rise in input costs and the consequences of consumer shift towards more affordable product lines and in doing so justified why we are unable to offer a higher pay deal in the current economic climate. As part of this discussion we also emphasized that we have a responsibility not to incur unreasonable cost price increases that would be pasted onto consumers and in turn fuel further inflation."

He added, "We offered a 3.8 per cent increase in line with the rise in the national minimum wage that is set by Government. This revised offer would ensure that the lowest earners maintained their premium above the national minimum wage as requested as a priority by Unite. In recognition of these exceptional economic pressures facing our valued employees we also offered a guarantee that there would be no redundancies in the next six months in addition to a number of other valuable benefits such as the early introduction of their new holiday entitlement."

The spokesman also said that any action would not disrupt distribution of whole birds that are packed at other sites.