The move by Dr Paul Mortimer is significant because he is a key adviser to the Department for Education and Skills’s innovation unit and has already pioneered many other radical changes to schools, including using cover supervisors to take lessons.

Dr Mortimer plans to rebuild Hollingworth high in Rochdale, one of the two schools where he is an executive head, in 2008 or earlier, so it can teach students all year round.

The school’s teachers and 1,200 pupils would still attend 190 days a year, the national standard. But the pupils would be split into eight mixed-year groups so their five terms and holidays would fall at different times.

Poorer families would be offered term-times that would let them take holidays in cheaper off-peak periods. Teachers would also be able to book holidays that coincided with those of their children, even if they were in other authorities.

Because the school would have fewer pupils on site at any time, it would be rebuilt to two-thirds its existing size.

“For the first year the school would have a Monday to Friday working week, but a year after that we would start lessons on Saturdays and a year after that on Sundays,” Dr Mortimer said.

“I imagine there might be some bank holidays that would remain sacrosanct, such as Boxing Day, but some teachers might be prepared to work then as well.”

Heads’ associations said the idea was feasible and fitted with the Westminster government’s drive to create extended schools. The Assembly government has set aside pound;3 million a year to pump-prime community and extended school projects in Wales. (But the National Union of Teachers said teachers would be angry to lose holidays and weekends.