Imagine John Lennon when he was 64

On the eve of what would have been his 64th birthday, his family, friends and fans have imagined what he would have been like had he survived. They came up with some intriguing ideas: a composer of musicals to rival Andrew Lloyd Webber; a bestselling author; a robe-wearing, ponytailed peace campaigner leading protests against the Iraq war; or perhaps still playing in a rock ’n’ roll band.

If he had survived, instead of bleeding to death on the pavement outside Dakota Building in New York on 8 December, 1980, after being shot by Mark Chapman, a reunion with his fellow Beatles would not have been out of the question, according to one of his biographers.

But whatever Lennon might have done, everyone agrees he would have continued to make his mark on the world.

Julia Baird, his half-sister, believes he could have become a best-selling author and toured the world with his two musician sons. "He would definitely have continued to play music," said Ms Baird, one of Lennon’s three half-sisters. "Who knows, he might have toured with Sean and Julian.

"I do think he would have continued to paint and write. Music was just one part of his genius. He was truly multi- talented and would have written his autobiography and maybe other books which would have been bestsellers. He was also a wonderful artist."

In terms of his celebrated style of dress, which could range from fur coats and cowboy hats to tight black leather, his sister was sure of only one thing: "I could never imagine him in a suit."

In comparison, Stanley Parkes, Lennon’s older cousin, to whom he was exceptionally close during his formative years, imagines him in a sports jacket with a buzz-cut hairstyle.

"I don’t think he would have kept the long hair," he said. "I imagine him with it tightly cropped. I also think he would have written more music, such as musicals. He was keen to expand into other areas."

A short haircut would have been to disguise the inevitable sign of aging, which the band remarked upon in the song’s celebrated lyric, "When I get older, losing my hair, many years from now ..."

However, in the opinion of Gerry Goldman, the director of the Beatles Story, the Liverpool museum dedicated to the band, he would be wearing robes, have a beard and ponytail, and would be fighting for peace. "He would be very concerned about world peace, but he would have had a more mature approach today than his bed-ins of the past," Mr Goldman said.

In the late 1960s, Lennon was a follower of the Maharishi Mahesh Yogi, and in 1969, he and Yoko Ono, his second wife, used their honeymoon at the Amsterdam Hilton to hold a bed-in for peace to protest against the Vietnam War.

When one million people marched through London in March last year in protest at the government’s decision to go to war in Iraq, John Lennon would have been in the front line, according to Bill Heckle, the owner of the Cavern Club, the Liverpool venue where the Beatles made their name.

"The man had his phone tapped by the British government in the 1960s because of his protests against the Vietnam War. His concern for world peace would only have deepened, and he would certainly have been on those marches.

"He would also have had enlightened views on health issues and the ethical treatment of animals. The irony is all the things about which he was concerned - the planet, peace and individual spirituality - have all become major issues today. He was ahead of his time."

As a resident of New York, the events of 11 September, 2001, would have devastated Lennon. "He would have been quick to lend his support to the fund-raising concerts that took place after 9/11," said Jim Henke, who as curator of the Rock and Roll Hall of Fame in the US, worked with Yoko Ono on a major exhibition dedicated to Lennon in 2000.

"The destruction of the twin towers would have deeply disturbed him," he said. "As a New Yorker, how could it not have? This was a city that he loved. But that wouldn’t have stopped him from coming out against the war."

The author of Lennon Legend, a biography of Lennon based on the Hall of Fame’s exhibition, Henke believes the Beatles could have re-formed in 1995 when the Anthology collection was released. "John Lennon would have been heavily involved in the project and it’s not hard to imagine them getting back together. He wouldn’t have sat in the background."

When I’m 64, like all Beatles’ songs, bears the writing credit Lennon/McCartney, but the tune was written by Paul McCartney when he was 15 and he later put lyrics to it in honour of his father’s 64th birthday.

Although it was first recorded for Sgt Pepper’s Lonely Hearts Club Band in 1967, it had been a favourite song played by the band during their early years on the club circuit. Yet, Lennon was dismissive of the song, saying: "I would never write a song like that." His son, however, recorded a version of it that was used by Allstate, an insurance company, in 2002.

While those surveyed by The Scotsman may have disagreed on Lennon’s contemporary clothes style or future plans, many thought he would still be married to Yoko Ono. The Japanese artist was criticised by Beatles fans as being partly responsible for Lennon’s decision to break up the band in 1969. However, she was, without doubt, "the love of his life" in the opinion of Gerry Goldman - although Stanley Parkes was adamant that any party for Lennon’s 64th birthday would have been held in Liverpool, not New York. "That was his home," he said. "He had 30 close years with his family. He had only ten years with Yoko."

One person who felt John Lennon would be no different from many other 64-year-old men was John Humphrys, the presenter of BBC Radio 4’s Today programme. "He would be a grumpy old b******, just like me," he said.

Mike Byrne, who, as a member of the Road Runners, was on the same bill as the Beatles at the Cavern Club, disagreed. He said: "John Lennon would still be in a rock ’n’ roll band.

"If Paul McCartney can still tour, so could John Lennon. McCartney is good, but only John Lennon could do dirty rock ’n’ roll."