Under the new Employment Act, which comes into force on Sunday, parents of under-sixes and of disabled children under 18 will have the right to request flexible working practices. It's something desperately wanted by the thousands of women teachers who give up work after having children. The Act holds out the prospect of job-sharing, as well as other flexible options not suited to teaching, such as home-working and shiftworking.
Asking, it has to be said, is not the same as getting. Although the new law will not guarantee entitlement to flexible working hours, heads who refuse will have to say why and could find themselves facing a tribunal.
With more than one third of teachers leaving within their first five years in the classroom, job-sharing would seem like a smart move in the retention game. But it is rare, especially in secondary schools - the majority of heads are male and seem less sympathetic to the demands of juggling work and family.
Gillian Boon, recruitment strategy manager for Norfolk, welcomes the legal changes. "Some headteachers have had negative experiences," she says. "But it's equally true to say that many are aware of the need and are trying to be supportive.
"In Norfolk, we have a tradition of small primary schools with teaching heads who do admin two days a week and job-share the teaching, so there is an awareness that it can work.
"Heads are concerned about continuity for exam classes, about ensuring there is planning time, about any extra cost there may be to an already overstretched budget.
"But as a head of 30 years myself, I found job-share partners so enthusiastic that they gave of their time for planning, although I wouldn't want to say they should. The fact is that job-share has a great retention value. If planned and supported it can be a definite bonus."
Norfolk is one of 11 local education authorities taking part in a job-share pilot with the recruitment specialists Flexecutive. Carol Savage, the company's chief executive, says that people who have contracts which fit in with their lifestyles will bend over backwards to make them work.
"Job-sharing is not a panacea for retention, but it is a useful tool," she says. "Our experience suggests that 30 per cent of heads like the idea; 40 per cent don't have time to think about it; and 30 per cent wouldn't touch it with a bargepole."
Of the 300,000 UK trained teachers who are not working in the classroom, Flexecutive estimates that more than half are women who left when they were aged 30 to 44. Many, the company believes, would return if they could work flexi-hours.
Last year, it launched an online service, free-to-teachers, to help them find job-share partners, as well as part-time or temporary posts. It has more than 2,500 schools on its books.
Flexecutive posts appropriate vacancies on its website and emails posts to teachers on its database. Schools are given a list of matching teachers. It also runs a job-share register so teachers can contact potential partners by email.
Debbie Bosher, head of Cheynes infant school in Luton, used to be sceptical about job-sharing, but experience has changed her mind.
"I was worried about the effect on the children, especially the youngest, whom I felt needed consistency," she says. "The reality has been very different. The children adapted very quickly - I think they are used to many adults taking on different roles before they even come to school.
"Now they get two teachers who are fresh, even on a Friday afternoon just before half term, and teach to their strengths."
Bernice Fuggle, head teacher of St John's Church of England first school in Stanmore, Middlesex, believes that job-sharing is a creative way of retaining good teachers, so when two staff asked to do so last year she was willing to consider it.
"If there is the choice I would always want a full-time class teacher in preference to a job-share," she says. "Still, these were two excellent teachers who had worked alongside each other for a period. It meant that in real terms I lost a teacher, but despite that it has definitely been a case of one plus one equals four."
The infants at East Hanningfield Church of England primary school in Essex have to switch positions on the carpet on Thursdays and Fridays, otherwise they can't see the whiteboard.Frances Tyas who takes them Mondays to Wednesdays is left-handed; her other half, Carita Hills, writes with her right. So on the last two days of the week, it means they have to shift.
But that's about the only inconvenience. The two teachers are convinced that they, their pupils and the school get a very good deal.
"It means the children get a teacher on full steam five days a week," says Mrs Tyas. "When one of us is on a course the other one will cover. I use my days off for my planning so that my evenings and weekends are free to spend on the family. And if we need face-to-face planning I go to school on my day off to meet Carita at lunchtime."
Join the debate about job-sharing on the Pay and Employment section of The TES website's Staffroom Forum: www.tes.co.ukstaffroom. See also www.spiked-online.comworklife
Flexecutive www.flexecutive.co.uk Tel: 0207 636 6744