Sir Paul McCartney wasn't "worried" about The Beatles losing money when they decided to retire from being a touring band.

In an interview with Shaun Keaveny for UK station BBC Radio 6 Music, McCartney said: "I don't remember being worried (about money) no.

"We tried to keep the live thing together, but it just finally became too much. So then it was like, OK, we are going to stop that, Now what can we do? We'll get into the studio, now we can really spend some time."

Drummer Ringo Starr insists they all felt it was necessary to get back into the studio so they could become better musicians.

He added: "We just made a decision that we were going to stop and go into the studio and get back down to playing together."

The two surviving members of The Beatles - who were joined in the band by the late George Harrison and John Lennon - also admitted that it took them a long time to learn how to tune their instruments properly for their concerts.

Asked how they are still able to stay so in tune when thousands of girls were screaming at the top of their voices, McCartney said: "It is amazing actually. I think we just had got better. I was thinking in the early gigs we did we weren't always in tune. It took a lot of gigs for us to suddenly go, 'Oh, I know how to tune up.'

"Some early gigs I remember we were really out of tune and there were people throwing coins at us. We picked them up."

And Ringo, 76, said that he is surprised how many bands nowadays have to use a different guitars for each song they perform, which was the opposite for The Beatles.

He added: "The most interesting thing is, whatever instruments the three of them walked on with they played every number.

"Now they put bands together and the guitarist has a guitar for every damn number. It is tuned this way, it's tuned that way. When I was out there George had one bloody guitar."

The 'Can't Buy Me Love' hitmakers' live days between 1962 and 1966 are the subject of Ron Howard's new documentary film 'The Beatles: Eight Days a Week -The Touring Years'.