Image copyright PA Image caption Social mobility initiatives, driven by better evidence, will be the priority, says Justine Greening

Education Secretary Justine Greening has announced the creation of an "evidence champion" who will make sure that decisions on improving schools in England are based on real evidence.

"We have a lot of evidence about what works in schools, but it's not spread within the school system," she said.

Sir Kevan Collins, chief executive of the Education Endowment Foundation, will be the first to take the role.

Ms Greening said her top priority would be to improve social mobility.

But, speaking at a Sutton Trust event in London, she said there would now be an "evidence champion" to make sure changes were informed by objective evidence.

'Social mobility emergency'

Ms Greening said the evidence champion would ensure more "value for money and impact".

"You can have some fantastic work and insights in a school in Exeter, but it won't necessarily get to a school in Newcastle," she said.

"We want to disseminate the best practice."

The role of expert opinion has sometimes been controversial in education.

During the debate over plans to reintroduce grammar schools, the government was challenged over whether it was refusing to accept the evidence of experts.

Former Education Secretary Michael Gove also prompted a debate, during the Brexit referendum campaign, with comments that "people have had enough of experts".

Ms Greening said the new "guiding mission" of the Department for Education would be addressing the lack of social mobility.

She said there was a "social mobility emergency" - a problem that in some respects had "gone backwards".

In particular, she warned of some parts of England with "entrenched disadvantage", where low skills and poor employment were found in a downward spiral alongside underachieving schools.

Ms Greening has previously announced 12 "opportunity areas", where attention will be focused on raising standards and encouraging better training and work opportunities.

These areas are Doncaster, Bradford, Fenland & East Cambridgeshire, Hastings, Ipswich, Stoke, Blackpool, Derby, Norwich, Oldham, Scarborough, and West Somerset.

Sir Kevan said his role would be to ensure the evidence of research was being applied.

"Let's start with what we know, rather than what we think we know," he said.

There had been much detailed work into the "blockages" in social mobility, said Sir Kevan, and this needed to be shared.

"It's another signal that we're being thoughtful and rigorous," he said. "Let's look at the evidence."

The Education Endowment Foundation was created to test ideas that would help to raise standards in disadvantaged areas.