Shaken Babies: What's the Truth?

Parents face jail or losing their children, if courts find them guilty of harming their babies by shaking them. One doctor who regularly appears as an expert witness for the defence is now herself on trial accused by the General Medical Council of giving unreliable evidence in shaken baby cases. Reporter Alison Holt has exclusive access to the neuropathologist at the centre of a fight about the diagnosis of shaking, she meets families where it has been proven and where convicted parents continue to protest their innocence.