Workers at the Overton museum were balloted over whether to take industrial action, including a possible strike on the next bank holiday, after museum bosses offered them an annual pay rise of 2.5 per cent, fixed for three years.

Union bosses slammed this as a "kick in the face" and said it amounted to a pay cut for around 100 workers.

This prompted a vote and 82 per cent of the Unison-represented staff said they would support industrial action stopping short of striking.

But 79 per cent of all union staff said they would back strike action. If it goes ahead, the strike is planned to last for 48 hours from midnight on Saturday, May 24.

Chris Jenkinson, Unison's Yorkshire regional officer, yesterday wrote to museum directors calling for last-minute talks.

He said: "Unless something happens at the eleventh hour, it looks like staff will be striking and it's likely to be the next bank holiday in May. This will have a major impact as it is one of the busiest weekends of the year.

"The last thing we want is for our members to have to take industrial action as it would affect the great name and reputation of the museum.

"But if the museum management is not prepared to sit down and talk sensibly, there's now a real prospect the museum could be closed for bank holiday."

According to Unison, the ballot over industrial action attracted a turnout of 90 per cent of union staff, some of whom are former miners.

Mr Jenkinson said: "They are being offered a pay cut against a backdrop of real success at the museum and are being rewarded with a kick in the face in terms of pay."

Museum bosses say they are bound by government guidelines which say public sector pay should not rise by more than two per cent, or 2.5 per cent over three years, and could lose vital grant funding if they break the rules.

But Mr Jenkinson said Unison felt the museum was free to set its own wages.

Museum director Dr Margaret Faull said the deal contained extra holidays for lower-paid staff.

Dr Faull said: "We have a management agreement with the government. If we don't follow that guidance they can withhold all or part of the grants."

Union and museum bosses are set to meet next week.

l Council workers across the country will be balloted on 'solid and sustained' strike action in June after Unison rejected a final pay offer of 2.45 per cent and 3.3 per cent for the lowest-paid staff.