A British woman, who launched a courageous campaign against knife and gun crime after her son was shot by unknown assailants, has been found stabbed to death, police in the northern city of Leeds said.

Pat Regan, a 53-year-old mother of six, founded the Leeds branch of the group Mothers Against Violence, a voluntary organisation giving support to those affected by violent crime, after her son Danny, then 25, was shot dead in December 2002.

Her body was found at her home in Leeds on Sunday evening. Police said a 20-year-old man was being held on suspicion of her murder, but did not confirm a BBC report that the suspect was her grandson.