A poll of more than 500 parents carried out by single parent family charity Gingerbread, found that 97 per cent had seen "no or very few jobs" advertised as being within school hours.

The survey, the findings of which were published in a report entitled Changing the Workplace: The Missing Piece of the Jigsaw, also revealed that 95 per cent had seen no or very few jobs advertised as a job share, while 62 per cent had seen no or very few jobs advertised at part-time hours.

Meanwhile, 97 per cent had seen no or very few jobs advertised as flexible in any other way.

"Perhaps the biggest problem for single parents is the continued lack of jobs that allow them to be there for their children when they need them," the report said.

It adds that with the government set to move an extra 100,000 single parents into work in 2011, by requiring them to look for work when their youngest child reaches five, flexible working opportunities are vital.

"Ambitions to have more single parents in employment and achieve cost savings can’t be achieved without it [flexible working]," the report said. "The coalition has promised to make flexible working available to all employees – we think that government should introduce this legislation before requiring single parents whose youngest child is five to look for work."

The report added that there should be an assumption that all public sector jobs should be advertised with the possibility of job share or part-time work, with managers required to set out a clear business case in situations where they consider it to be impossible.