Giving teachers more time out of the classroom could encourage them to teach in challenging schools, a study has found.

More free periods would be an incentive for staff to spend at least part of their career in this type of school.

It also suggests that many teachers believe that staff who improve pupils' results and boost progress should be given cash bonuses.

The findings come in a new report by the Sutton Trust which is based on a survey of almost 1,500 teachers.

The study, which will be presented at an international education summit in London today, reveals that a third of those polled said that the most important thing government could do to encourage more teachers to work in challenging schools is to offer lower contact hours - such as free periods.

This rose to 41% among the secondary school teachers questioned.

A similar proportion (35%) said that the Government should offer better pay or bonuses.

The poll reveals that around a fifth (21%) believe that teachers who improve progress and results should get a cash bonus of £3,000, while 15% thought that staff should get a 3% pay rise.

And nearly a quarter (23%) thought that team bonuses of £20,000 for a primary school and £50,000 for a secondary should be on offer.

Nearly three in 10 (29%) thought there should be no extra reward for improving pupils' results and progress.

The study, part of a research project by academics at Cambridge University, also concludes that experienced teachers are more effective in the classroom than those in the first few years of their career - and they are more likely to teach in advantaged schools.

Sutton Trust chairman Sir Peter Lampl said: "We know that good teaching is the most important factor in raising the achievement of all pupils but particularly those from disadvantaged backgrounds. Today's research shows that teachers in more advantaged schools are likely to be more experienced, which generally leads to more effective teaching.

"In order to improve the performance of disadvantaged pupils it is vital that theses pupils have access to the best teaching. Today's new polling finds that teachers think financial incentives are the most effective way to attract the best teachers to teach in the most challenging schools."

Report author Professor Anna Vignoles said: "Teachers are the heart of an effective education system. There are real challenges around recruitment, retention and improving teachers' satisfaction with their jobs, particularly in our most disadvantaged schools."

The findings come amid concerns from headteachers and education experts about a growing teacher shortage, especially in disadvantaged schools.

The Association of School and College Leaders (ASCL) has warned that growing teacher shortages are having a damaging impact on children's education, while Ofsted chief Sir Michael Wilshaw has also raised concerns about the issue, arguing that improvements to England's education system will be undermined if action is not taken to address the issue.

Education Secretary Nicky Morgan has acknowledged that many schools are struggling to recruit good teachers, but has also warned that talk of a "crisis" could put people off wanting to join the profession.

Schools Minister Nick Gibb said: "Nothing is more crucial to improving outcomes for pupils than good teachers, and we want all young people, irrespective of birth and background, to benefit from the best possible teaching.

"To ensure this happens we have expanded the Teach First programme, given schools unprecedented freedom over pay so they can reward their best staff and invested in a range of programmes to help develop talented teachers into great leaders. We have also set up the National Teaching Service to recruit 1,500 high-quality teachers by 2020 in the regions which need them the most.

"We continue to look at what more we can do to recruit and retain high quality teachers wherever they are needed - and our efforts to tackle workload are an important part of that."