One of the UK’s leading unions has launched a campaign to get chancellor George Osborne to deliver a promised pay increase of £250 to everyone in the public sector earning under £21,000.

The chancellor made his pledge last June,but local government employers do not believe they will get the pay increase this year, marking the second year of a freeze on employee benefits and pay.

Around 40 per cent of school staff in England are employed by schools and the union wants Michael Gove to deliver the £250 to them. It said that while NHS staff and civil servants are getting the increase, local government, school and college staff are not.

Christina McAnea, Unison’s head of education, said: “There were no caveats to the Chancellor’s promise. Osborne has to deliver on his promise.

“The government’s position in indefensible – our members do vital jobs to support the public, pupils and their families and they deserve to be treated better.”

Last week, Unison claimed via information from the Office for National Statistics that the average worker is £750 worse off due to the rising cost of living, as inflation hits 5.1 per cent.