Day the world was robbed of a music icon

Mark Chapman had a clutch of reasons to explain why he shot John Lennon dead. But it seems really he was just another American crazy, a malign nobody with a twisted ambition to make some sort of impact on the world.

It is 40 years ago today that the former Beatle was gunned down outside his New York home, the landmark Dakota building on Manhattan's Upper West Side.

As Lennon returned from a late night recording session, Chapman was waiting. He pulled out a .38 calibre handgun from under his coat and fired five times.

Lennon staggered about five feet to a small guard's booth in the courtyard of the building.

"Do you know what you just did?" the doorman asked the gunman.

"I just shot John Lennon," he replied, and threw down the gun.

As the dying Lennon was cradled in the arms of his wife Yoko Ono he whispered: "Help me." Police officer James Moran rushed the star to hospital in his police car. Yoko was crying and shouting repeatedly: "Tell me it isn't true." Terribly injured, Lennon was beyond help and died in her arms.

Chapman, 25, was arrested by patrolman Steve Spiro. He offered no resistance and, according to witnesses, was smiling when he was driven away.

News of Lennon's murder quickly spread around the world. He was a legend who to many was the cutting edge of the Fab Four. After the Beatles break-up, some deeply personal and haunting solo albums followed, and one song in particular, Imagine, is an enduring classic which has been recorded and sung by a wide variety of singers.

Then in the mid-1970s Lennon abruptly gave up songwriting and recording.

"I shut up and learned to cook and be with the baby, and allowed the feminine side of myself to exist," he told one interviewer.

At the time of his death he had re-emerged into the limelight with the promise of a new wave of creativity after five years as a semi-recluse from the music scene.

His optimism for the future was embodied in a song, Starting Over, included on his album Double Fantasy which had been an instant hit when it was released just three weeks before his death, signalling a reboot of his career.

Lennon, who was 40, was murdered in a city he loved. He loved New York's buzz, the diversity, and the 24-hours-a-day culture.

He had left Britain in 1971. The administration of US President Richard Nixon had tried to deport him on the grounds that he had a 1968 conviction for cannabis possession – Lennon's stance against the Vietnam War didn't help either – and had he returned to the UK he might never have been able to get back into the United States.

However, after a long battle in 1976 he secured his green card – his permit to live and work in America – which meant at last he could travel freely. But Lennon never did return to Britain.

After his death Double Fantasy unsurprisingly became a posthumous monster hit, topping the chart in both America and Britain. It went on to sell the most copies of any of his solo albums.

There were effects on the three surviving Beatles. Paul McCartney feared for his life, and was spooked when he saw gunmen near his remote farm. It turned out to be Army manoeuvres. Lennon's death also inevitably changed public perceptions of him, giving him a sort of martyr's illumination which the others of the Fab Four did not have.

As for Mark Chapman, he was a security guard from Hawaii, a Beatles fan who had idolised Lennon, before turning against him.

As Lennon had left the Dakota earlier that fateful day, Chapman was there. He asked him to autograph his copy of Double Fantasy. Lennon wrote "John Lennon 1980" on the sleeve. A photographer took a famous picture of him doing so.

Hours later, as Lennon returned home, Chapman was still there, this time with murderous intent.

No consistent, coherent motive has ever emerged. When arrested he had a copy of the J D Salinger novel The Catcher in the Rye, a portrait of a young man at odds with the process of growing up.

It seems he may have had alternative victims lined up on a hit list. He was obsessed with Todd Rundgren and had tried to find him in the days before the killing. Chapman was wearing a promotional T-shirt for Rundgren’s album Hermit of Mink Hollow when he was arrested.

He pleaded guilty and in 1981 was given a sentence of 20 years to life. He remains in jail, and Yoko Ono has pleaded for him not to be released, partly for fear for her own safety and that of her sons, but also because Chapman could be subject to revenge attacks.

In August he was denied parole for the 11th time. He will next be eligible to apply in two years, when he will be 67.