Statistically, she was just another victim of violent Britain, but the bleak irony of Pat Regan’s death will be lost on no one.

The 53-year-old grandmother made it her life’s mission to wipe guns and knives from the streets. Two days ago, she was found dead from multiple stab wounds.

Mrs Regan’s anti-violence campaign, triggered after the fatal shooting of her own son in 2002, led to her being courted by Cabinet ministers, praised by royalty and photographed with Tony Blair.

As a leading member of Mothers Against Violence, she took her message into schools, prisons and young offenders’ institutions. She led street marches, gave interviews on radio and television, held one-to-one sessions with worried parents and pleaded for more funding to support her work.

Friends have described tripping over boxes in her tiny flat that were overflowing with letters of thanks from people whose lives had been changed by contact with the mother of five. The boxes were still there at 7pm on Sunday when police were called to her maisonette in a four-storey council block on the edge of Leeds city centre.

Officers found Mrs Regan lying dead. Her 20-year-old grandson, who has a history of mental health problems, is being held on suspicion of her murder.

Police tape fluttered half-heartedly around the block of flats. Uniformed officers stood chatting outside the ground-floor entrance. Weeds grew through the paving blocks and a cat dozed on an adjoining wall.

Windows on the second floor had been masked with brown paper and grey plastic sheeting. Traffic roared past on the main road.

A few hundred yards from the murder scene lay the imposing newskyscrapers of 21st century Leed. But brown-brick Marlborough Grange belongs to an older, more apologetic age. It provides homes for ordinary people. Mrs Regan was one of them. As her close friend, Patsy McKie, told The Times yesterday, she just happened to do something extraordinary with her life.

Danny Regan, her youngest son, died aged 26 in 2002 when a killer with a pump action shotgun burst into his home in St Helens, Merseyside, and shot him in the chest. His death, which remains unsolved, bore all the hallmarks of an underworld hit.

Mrs Regan would speak later of the mourning that knew no closure. With the murder of a child, she said, the pain never goes away. She used it to drive her forward. A group of mothers in Manchester, their children the victims of gun crime, had formed a group, Mothers Against Violence, to highlight the growing gun and knife culture among Britain’s youth. Mrs Regan met them and offered to form her own branch in Leeds.

She was no saint — she had a criminal conviction — but friends say she had a burning desire to awaken society, particularly the young, to the dangers of carrying weapons. When she spoke it was always blunt and from the heart. People listened.

She took a particularly strong line with those, particularly rap artists, who glamorised guns, drugs and gangs. “I say to all these youngsters: you want to play with knives, drugs and gangs? Then be prepared to die or to go to jail for a very long time. There are no success stories,” she told one interviewer.

Tributes to Mrs Regan were paid yesterday by Leeds MPs, police officers and Jacqui Smith, the Home Secretary. Hilary Benn, the Environment Secretary and MP for Leeds Central, said she “made a huge impression on everyone she met”. Shane Regan, her son, wept as he described his mother as one of the most genuine people you could meet: “She had dedicated her life to stopping violence like this. I’m heartbroken that she’s not here any more. She died for what she believed in and what she was trying to stop. She was the best'” he said.

Mrs McKie, 60, whose own son was shot dead in Manchester, aged 20, nine years ago, said that Mrs Regan was “a vibrant, passionate and amazing woman who loved her community.

Rakeem Regan, 20, is also being questioned about the stabbing of a member of staff at Leeds railway station on Sunday.

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