A second police force is conducting an urgent review of all its rape cases after a series of blunders led to the collapse of the prosecution of an Oxford University student.

A judge criticised Surrey police and the Crown Prosecution Service (CPS), giving them 28 days to explain what had gone wrong or face ‘action’.

It prompted both police and CPS to apologise for ‘mistakes’ in the investigation into a claim of rape made against Oliver Mears, 19.

Mr Mears, of Horley, Surrey, had spent two years on bail accused of raping and assaulting a woman in July 2015 when he was only 17. The chemistry student, who left St Hugh’s College Oxford because of stress, was officially declared not guilty and the case against him dropped just days before the start of his trial.

Surrey police’s decision to examine all current rape cases follows a review by Scotland Yard of every one of its sex crime investigations that was prompted by the collapse of two prosecutions in a week.