It was just one of the 400 or so songs, jams and fragments played during the infamously fractured recording sessions, but it would take another two years for Lennon to finish the song that would become an epitaph of sorts for the late singer-songwriter.

The seeds of the song lay in a book by his wife Yoko Ono called Grapefruit. Published in 1964, it was a piece of conceptual art listing a series of instructions for the reader, in which the word "imagine" featured prominently.

"Yoko actually helped a lot with the lyrics, but I wasn't man enough to let her have credit for it," Lennon confessed to reporter David Sheff during a series of interviews for Playboy magazine published just two days before Lennon was shot dead on December 8, 1980.

In early 1971, Lennon finished the lyrics (and Ono's input was officially credited in 2017) and in June that year, he recorded takes at the purpose-built studio at his Tittenhurst Park mansion home — sound engineer Eddie Veale, who helped construct the studio, called it "The first professional home studio in the UK".

Long-time friend and Revolver album cover designer Klaus Voorman played bass and future Yes drummer Alan White played drums, while acclaimed session pianist Nicky Hopkins added electric piano that was rejected for the final take.

On July 4, a subtle layer of strings was added, and the song was finished.

You may say I'm a dreamer

In October the song was released as a single around the world except in the UK, reportedly to keep the focus on Lennon and Yoko's other peace anthem Happy Xmas (War Is Over). 

The song went to number one in Australia and Canada, but stalled at number three in the US. It reached six on the charts in the UK when it was finally released as a single in 1975 to help promote the Lennon compilation album Shaved Fish.

Lennon seemed to think the initial response was underwhelming, especially compared to the run of hits he had with his previous band, but he was particularly proud of Imagine.

"I came up with Imagine, Love, and those Plastic Ono Band songs — they stand up to any songs that were written when I was a Beatle," he told Sheff.

And no religion, too

The lyrics of Imagine were the latest stop on Lennon's spiritual journey.

He was raised a Christian, hung out with the Maharishi and had dabbled in counter culture, the Tibetan Book of the Dead and various forms of therapy and meditation.

But Imagine encapsulated his world view at the time, summarising the bed-ins, protests, and political ideals that had been  increasingly seeping into his music since The Beatles' track Revolution in 1968.

Lennon once described the song as "anti-religious, anti-nationalistic, anti-conventional, anti-capitalistic, but because it is sugarcoated it is accepted".

A brotherhood of man

For musician Emmanuel Kelly, Imagine is the song that kickstarted his career. 

Born in Iraq, found by soldiers as a baby in a box, half-dead with under-developed limbs, Kelly first came to public attention thanks to a moving performance of the song on the Australian TV version of reality music competition The X Factor.

He had planned to sing a different song for his TV debut but the rights couldn't be cleared, so he had to sing his back-up song — Imagine.

Kelly has even performed the song on stage with UK megastars Coldplay. 

"That was pretty nuts. It was a super-incredible, powerful experience," he said.

Imagine no possessions

Joe Goodden, who runs the Beatles Bible website and wrote the book Riding So High — The Beatles & Drugs, said: "Imagine will always be John Lennon's signature song."

"It's a simple message, a secular hymn to mankind's better nature, which resonates because of its simplicity and earnestness," Goodden said.

"I don't think Imagine will ever feel dated, because it speaks to our universal need for a better future.

"The Beatles were masters at making us feel connected, whatever our age or background, and in finding those feelings which resonate across borders and oceans - Imagine is Lennon's most effective example of this."

"John Lennon wasn't saying he was perfect, he was saying we can strive for a better world if we put aside our differences and pull together," he said.

Nothing to kill or die for

The final song Lennon ever played live was Imagine.

The former Beatle effectively retired from performing and recording in 1975 to focus on raising his son Sean, but was in the midst of a comeback when he was murdered in 1980, having just released the album Double Fantasy with Ono.

As a result, his last live performance was in 1975 at a TV special to honour UK entertainment impresario Lew Grade where he played just three songs, the last of which was Imagine.

In the wake of his death, the song returned to the charts around the world, going to number one in the UK and Ireland, and over the next 40 years the song would chart again and again.

Since 1980, it has re-entered the Australian ARIA top 100 four times and the UK charts five times.

Lennon's friends Elton John and David Bowie both performed the song live after Lennon's death, and the song has become an anthem for troubled times.

After the September 11 terrorist attacks in New York, Rolling Stone's David Fricke wrote: "Imagine has emerged as a new national hymn, a strong, quiet counterweight to the institutional psalms and fight songs — The Star-Spangled Banner, God Bless America, America the Beautiful — that have filled the air since the terrorist attacks."

Story By | By Matt Neal