The Prime Minister has stepped in after an exchange between ministers over the handling of alleged Islamist extremism in Birmingham schools.
A Downing Street source said David Cameron was "keen to establish the facts" after Theresa May wrote to Michael Gove questioning why his department had not acted on warnings of a supposed plot by Islamist extremists.
May's letter inquired about evidence that the Department for Education knew of the 'Trojan Horse' allegations in 2010 and asked: "If so, why did nobody act?"
As the letter emerged the pair took the unusual step of issuing a joint statement insisting they were "working together" on the issue.
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