The singer added that he understood the reason why record label Decca declined to sign the band in 1962.

"We obviously weren''t that good. We were formulating it all,” the Sun quoted him as saying in an interview with Xfm's Ian Camfield.

He added: "You wouldn't have thought we were that great. You'd have turned us down if you were a record company. And they did - Decca turned us down!"

However, the Fab Four later signed with EMI''s Parlophone label, with the assistance of producer George Martin.

The band then headed to play a 48-night residency in a Hamburg, Germany, club.

McCartney said: "When we first went to Hamburg, and there''d be no-one in the club.

"You'd see a couple of students, maybe a guy and his girlfriend, and they''d look in a bit tentatively, look up at the price of the beer, see it was too much and start walking out.

"So we'd go, 'Come on, everybody, get back in here! It''s all happening!'

"So we'd learned to attract an audience. After a few weeks, we''d be really packing those clubs.

"It taught us that game of how to win over an audience.