David Cameron has pledged to build an extra 500 free schools if the Conservatives win the election in May.
In a speech to be given today (March 9), the Prime Minister will also announce the approval of 49 new free schools at the same time as a report by the right-wing think tank Policy Exchange concludes the innovation is driving up standards at primary and secondary level.
However, the drive has been criticised for using up 'a huge amount of resource' and for schools being built where they're not needed.
Free schools have been the big education experiment of this Government with more than 400 being approved.
The scheme allows parents and teachers to set up their own schools, and has created more than 230,000 places since 2010.
Mr Cameron will say: "If you vote Conservative, you will see the continuation of the free schools programme at the rate you've seen in the last three year.
"That means, over the next parliament, we hope to open at least 500 new free schools resulting in 270,000 new school places."
According to Policy Exchange nearly three quarters (72 per cent) of all open or approved mainstream free schools are in areas with a projected lack of places in the future.
But critics say some schools are being set up in areas where there is no need for them, that they are unaccountable and the initial findings do not warrant expanding the programme.
Henry Stewart from the Local Schools Network said: "It you look at the data for both primaries and secondary schools, free schools don't have any effect on the other schools in the area, but what they have done is they've used up a huge amount of resource.
"Some £1.7bn is the capital spend on free schools to date and the National Audit Office found that 52VIRTUAL-UKArticleAdsVIRTUAL-SchoolfinderWidget-leftVIRTUAL-DealsCategoryWidget%