Union leaders have been forced to reschedule a strike ballot for Warburtons staff after voting papers were held up by Royal Mail stoppages earlier this month.

The original two-week ballot was open from 10-24 October, but the Royal Mail strike meant there was no post from 4-9 October.

Tens of millions of items were left undelivered during the strike, including many of the voting papers for the more than 1,000 members of the Bakers, Food and Allied Workers' Union who work at Warburtons' 13 bakeries across the country.

"We found that a large percentage of members didn't receive a ballot paper," said Roy Streeter, BFAWU regional officer. "There was action going on that was out of our control. Obviously we have to be fair to our members and it's important to get as many members to take part in the ballot as possible."

On Tuesday, the BFAWU served Warburtons with a seven-day notice of a new ballot, with the poll now to run from 5-19 November.