Unite said 1,300 workers are to walk out in the strike action

Members at sites in Great Witchingham, Norfolk; Holton, Suffolk; and Dunstable, Beds, are to hold the 24-hour strike on Thursday 15 November.

Unite said the move, over a 2% rise in wages, could threaten turkey supplies to supermarkets over Christmas.

Bernard Matthews said any lost business could lead to job losses.

'Strong pay offer'

Miles Hubbard, regional officer for Unite, said: "The workforce has held this company together through a most challenging year, so have been particularly angered by management's imposition of what is effectively a pay cut.

"They came under a good degree of pressure from management not to vote for strike action, so we urge Bernard Matthews to return to us with an improved pay offer which they have thus far refused to do."

The company said its pay offer had been fair when the business had not had a good year.

A company spokesman said: "Bernard Matthews has made a very strong pay offer in light of its current business position to the union, the T&G section of Unite.

"A 2% rise in wages backdated to August, an additional recovery bonus at year end and a review of the situation in February 2008.

"The consequence of lost business is potential job losses, which is not what anyone wants.

"The union's strategy of fighting for a pay award when there are no additional finances to fund one appears to be at odds with their desire to work in the interest of our employees' future."