The biggest rail strike in three decades is expected go ahead after last-ditch talks failed, the RMT union said.

A walk-out by 40,000 workers on Tuesday, Thursday and Saturday will cause “total misery” according to Transport Secretary Grant Shapps.

Mr Shapps said the walk-out was “totally wrong” and would inconvenience millions – including those like his own daughter who are taking exams.

The strike is the result of a dispute over pay, jobs and conditions. The RMT is asking for a pay rise of 7% – lower than inflation but higher than that being offered by employers.

RMT general secretary Mick Lynch said latest offers from publicly-owned Network Rail and private train operating companies had been rejected.

Mr Lynch blamed Mr Shapps for cutting billions of pounds in funding for public transport.

“This dispute has been manufactured by Shapps and by government policy,” he said.