Twenty five years ago today, Mark Chapman walked up to John Lennon in New York and destroyed the dreams of millions around the world. Nick Morrison looks at the impact of the life - and death - of a musical genius.

EVEN before John Lennon's death had been announced, horrified fans had rushed to the courtyard of the Roosevelt Hospital in New York, some on their knees praying. That night, they gathered outside the Dakota building where he had lived, and where he had been shot just hours earlier.

The newly-widowed Yoko Ono sent word that their singing was keeping her awake and asked that they reconvene instead in Central Park the following Sunday for ten minutes of silent prayer. It was to be a vigil repeated all over the world.

"It produced what at the time seemed an astonishing worldwide response, and even now, looking back, it still seems astonishing," says Richard Middleton, emeritus professor of music at Newcastle University. "There were vigils and demonstrations all around the world.

"Now we have seen similar reactions to celebrity deaths, like Princess Diana's, it seems that perhaps this was the first. You can't really imagine that sort of response before the global media coverage we have got now, but people reacted in a way which was previously limited to tragic events involving people they actually knew.

"Lots of people felt they knew John Lennon, even though they never met him."

It was late afternoon on December 8, 1980 - 25 years ago today - that Mark Chapman met Lennon outside the Dakota building in New York. In his hand, Chapman held a copy of Lennon's Double Fantasy album. After Lennon autographed the record - an act captured by a photographer - he left for the recording studio. Chapman hung around outside the building for the rest of the day.

At 10.50pm, Lennon and Ono's limousine pulled up at the entrance to the Dakota. As Lennon walked towards the door, Chapman called out "Mr Lennon". Lennon turned and witnesses described how Chapman crouched down and fired five times at his back and shoulder. One bullet missed, but the other four hit their target.

Lennon staggered towards the building and collapsed, gasping, "I'm shot, I'm shot." As horrified onlookers arrived, one of them asked Chapman what he had done. "I've just shot John Lennon," he replied. He calmly took off his coat, got out a copy of JD Salinger's Catcher in the Rye, and started reading.

Police were on the scene within minutes and took Lennon to hospital. But the blood loss was too great, and Lennon died of shock.

Chapman, who was sentenced to life with a minimum of 20 years, had been obsessed with Lennon, even marrying a Japanese woman because she reminded him of Ono. Haunted by fears of his own insignificance, he had set out to be somebody, and succeeded. He is still in prison, his requests for parole having been turned down three times.

But if the reaction to Lennon's death was partly in response to its brutality, it was also a reflection of the way he had touched lives around the world, both through his music and his campaigning.

"Most people would agree that he was one of the greatest songwriters in popular music," says Prof Middleton. "And although he never claimed to be a virtuoso guitarist, he did claim, probably rightly, to be one of the best rhythm guitarists rock music ever saw.

"And he stands out as one of the most original and powerful male singers in rock music. He developed a style of his own that was recognisable and covered a wide spectrum. He could do hard rock songs but he could also do lyrical ballads.

"If you were to single out the individuals who stand out for their achievements in popular music and their influence, you would probably say Elvis, Bob Dylan and John Lennon."

Lennon's political activism became more prominent towards the end of the 60s, and contributed towards his elevation to iconic status. Hand in hand with his music, he became an increasingly radical figure, with the anti-war anthem Give Peace a Chance, the anti-sexist Woman is the Nigger of the World, and the Utopian Imagine, which became an anthem for anti-war movements.

"His music got intertwined with his political stance, and that clearly was a large part of the reputation that still survives, and also that fed into the reaction to his death," says Prof Middleton. "People regarded him as a figure of much wider importance than just a musician."

And his appeal has not diminished with his death. In 2002, Liverpool renamed its airport John Lennon Airport, and the same year he was 8th in a BBC poll to find the 100 Greatest Britons.

But in some ways his early death, and the manner of it, has ensured his reputation would be preserved, just as James Dean's status was enshrined by his death 25 years earlier. "For most of the 70s he was gradually fading from view, and although it is impossible to know what would have happened, my guess is that had he lived that would probably have continued," says Prof Middleton.

"It is hard to think what he would have done in the 80s and 90s that would have brought him back to the front of popular consciousness. More likely, he would have continued living in semi-isolation."

Had he lived, Lennon would have been 65 earlier this year. As it was, he will forever be the angry dreamer, fighting for a better world, and yearning for a better place.