Staff at exam board AQA are to stage a 72-hour walkout over pay which union leaders warn could affect the delivery of thousands of GCSE and A-level results.

Members of Unison will walk out for three days, from Friday July 29 to Sunday July 31.

The union warned industrial action is likely to escalate unless talks are reopened.

Many of the staff involved say they are struggling to make ends meet following successive below-inflation pay awards, Unison said.

Staff were given an increase of 0.6% last year, with 3% offered this year, which Unison said is a real-terms pay cut.

Read more: North Yorkshire factory worker left with shattered teeth after horror vape incident

Unison official Lizanne Devonport said the workers have been left with “no other option” but to strike.

“Pay has been falling behind prices for years and 3% isn’t a wage rise, with costs spiralling it’s a pay cut,” she said.

“Things are so bad staff are fear ful they will no longer be able to make ends meet.

“Workers only strike as a last resort. They’d rather be doing the jobs that they’re proud of. They don’t want to disrupt students and know how important exam results are to them.”