The Beatles’ “last recorded” song is on track to top the singles chart after outselling the rest of the top five combined in its opening weekend.

Now And Then, originally written and sung by John Lennon and later developed by his fellow band members – including the late George Harrison – was finished by Sir Paul McCartney and Sir Ringo Starr decades after the initial recording was made.

Following its release on Thursday, it is on course to become their 18th number one single, according the Official Chart Company’s first look.

It would also be their first chart-topper in 54 years, with the last being The Ballad Of John And Yoko in 1969.

Among their previous number one songs are classics such as Hey Jude, All You Need Is Love, Yellow Submarine and Help!

The remastered track was sourced from a Lennon demo which was recorded in the late 1970s at his home in New York’s Dakota Building.

After his death in 1980 aged 40, Lennon’s wife Yoko Ono gave the recording to the remaining Beatles in 1994 along with Free As A Bird and Real Love, which were released by the band in the same decade.

During this period, Harrison, Sir Paul and Sir Ringo recorded new parts and completed a rough mix for Now And Then with producer and musician Jeff Lynne.

Beatles fans in Liverpool for a special midnight launch event for the release of Now And Then (Peter Byrne/PA)

However, the band did not release the song and cited issues to do with extracting Lennon’s vocals and piano due to limited technology at the time. Harrison later died in November 2001 aged 58.

Filmmaker Peter Jackson’s recent Beatles documentary used audio restoration technology that allowed for vocals, music and conversations by the band to be isolated, a technique which was later used for Now And Then.

The song, which includes Harrison’s electric and acoustic guitar recorded in 1995, was finished by Sir Paul and Sir Ringo last year.

A music video for the song was also created by Jackson which sees the Fab Four reunited as Lennon and Harrison can be seen playing instruments alongside recent footage of surviving members Sir Paul and Sir Ringo.

Sir Paul McCartney and Sir Ringo Starr (Yui Mok/PA)

In an interview with The Sunday Times, Sir Paul said: “I like the idea of not letting go of each other.

“You know, when you have somebody you love so much. In many cases it’s a relative, and even though they go, you don’t want to let go – that’s what people say when somebody dies.

“They’re in your memory, always in your heart. And, yes, that’s certainly true of me and the boys.”

Reflecting on how he would like the band to be thought of, he added: “I remember the Beatles, I remember joy, talent, humour and love.

“And if people remember us for those things I’d be very happy.”

Sir Ringo said he would like for the group to be remembered “with love”.

The drummer added: “How many streams did we do last year? One billion? Three billion? It blows me away. The beat’s still going on, you know?”