Thousands of young people have brought parts of London to a standstill with a demonstration against knives and guns.

About 5,000 protesters marched from Trafalgar Square to Kennington Park in the south of the capital to call for an end to the violence that has already claimed the lives of 16 London teenagers this year.

The demonstrators, many members of the Seventh-Day Adventist Church, marched down Whitehall to Westminster to the loud accompaniment of a marching band.

As they reached Parliament Square, the protestors sang When The Saints Go Marching In.

Protesters travelled to London from all over southern England, with groups from Portsmouth, Milton Keynes, Luton and Ipswich among those represented.

Anti-gun campaigner Pat Regan, who was stabbed to death last Sunday, was originally due to address today's event.

Among those in the crowd was Rosie Ogazi, the sister of 21-year-old student Anthony Ogazi, who was also stabbed to death in south London last month.

The father of 15-year-old schoolboy Kiyan Prince, who was knifed to death outside his northwest London school in May 2006, addressed the crowd.

Mark Prince spoke of the "void" that his son's death had left in his heart.

But he said he has forgiven Kiyan's killer thanks to his faith in God, saying: "If it means I have to forgive the guy who killed my son, then that's exactly what I'm going to do because I need some mercy myself, I need some forgiveness myself."

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