Ministers have asked tour operators to reduce the difference between peak and off-peak prices following headteachers’ concerns that pupils are increasingly missing school to go on cheaper holidays. But the Association of British Travel Agents, which represents the travel business, described the request as “very awkward” while one London travel agent said it would be “a miracle” if tour operators complied.

The controversy blew up when headteachers announced that the practice of taking children on holiday during term time has become “the norm” and Education Secretary David Blunkett condemned parents who did so.

According to the National Association of Head Teachers one secondary school alone recorded more than 2,000 sessions lost to term-time holidays in 199798.

To the Government’s embarrassment, it emerged that even the children of the Prime Minister and the Home Secretary missed some schooling this week because of family holidays.

Ministers want ABTA to place warnings in travel brochures about the dangers of children missing school. But an association spokesman said tour operators might be reluctant.

Travel agents also say the industry could not cope if every family took their break during the summer holidays. The shortage of airline seats and hotel beds would cause prices to rocket, Peter Shanks, managing director of Going Places, said.

Some families were forced to holiday during term time due to financial or work constraints.

Mr Blair’s holiday drew sharp criticism from headteachers. Speaking on Radio 4‘s Today programme, David Hart, NAHT general secretary, said cabinet ministers should “sing from the same hymn sheet” and endorse Mr Blunkett’s stand.

“Whatever the reason maybe it’s important that children are there in school during term time and that includes the first day of term - that’s a very important day in the life of a school,” he said.