A British court has overturned the murder conviction of a woman serving a life sentence for killing her husband.

Sally Challen was convicted in 2011 of killing her husband Richard with a hammer. She admitted the slaying but denied murder, saying her spouse had controlled and humiliated her for 40 years.

On Thursday three Court of Appeal judges said a psychiatrist had testified that Challen was suffering from two mental disorders at the time of the killing — evidence that was not available during her trial.

The judges quashed the conviction and ordered a retrial.

Outside court, Challen's son David said it was "an amazing moment."

He said "the abuse our mother suffered, we felt, was never recognized properly and her mental conditions were not taken into account."