1. Impossible as it may sound there are still Beatles songs unreleased - the most notable ones being Carnival of Light (an experimental piece recorded on 5 January 1967 for The Million Volt Light and Sound Rave) and a 27-minute jam of Helter Skelter. A John Lennon composition the three surviving Beatles worked on in the early '90s prior to the Anthology release called Grow Old with Me also remains unreleased.

2. The Beatles (or at least half of it) sang for the Rolling Stones: Lennon and Paul McCartney provided backing vocals to the 1967 single We Love You.

3. Besides writing hundreds of songs for the Beatles, Lennon and McCartney also wrote dozens of songs for other artistes such as From A Window (Billy J. Kramer with The Dakotas), One and One Is Two (The Strangers with Mike Shannon), Step Inside Love and It's For You (Cilla Black), Come and Get It (Badfinger) and Woman (Peter and Gordon).

4. The Beatles’ third studio album A Hard Day’s Night is the only one to exclusively contain Lennon-McCartney compositions.

5. Paul is not McCartney's first name, James is. Lennon changed his middle name from Winston to Ono after marrying Yoko Ono in 1969.

6. At the end of Strawberry Fields Forever, Lennon is heard mumbling what sounds like "I buried Paul", which helped fuel the 'Paul is Dead' rumours. He's actually saying "cranberry sauce".

7. The only Beatles single to ever feature another musician on the credit is Get Back/Don't Let Me Down (credited to The Beatles with Billy Preston). Preston, recruited by George Harrison to ease the growing tensions in the band, played the Hammond organ on both songs.

8. Two days after Sgt Pepper's Lonely Hearts Club Band released, Jimi Hendrix opened his set at London's Saville Theatre with the title track, something McCartney considers his "single biggest tribute".

9. The final version of Strawberry Fields Forever was created combining two takes of the song in two different keys and speeds - a remarkable achievement considering the equipment and technology of the time - but still failed to fully satisfy Lennon.

10. The only Beatles track to be credited to Lennon and Harrison is an early instrumental called Cry for a Shadow recorded in 1961 when the band was backing Tony Sheridan. Flying and Dig It are the only two tracks to be credited to all four Beatles.

11. The BBC banned several Beatles songs - I Am the Walrus (for the use of the word 'knickers') and Fixing a Hole, Lucy in the Sky with Diamonds and A Day in the Life (all for alleged drug reference).

12. The working title for the film Help! was Eight Arms to Hold You.

13. For the Sgt Pepper album cover, cutouts of Adolf Hitler, Mahatma Gandhi, and Jesus Christ were requested by Lennon, but ultimately they were left out, though a cutout of Hitler was made for use.

14. Ringo Starr was the first to actually leave the group, walking out in 1968 during the acrimonious White Album sessions. As a result, the remaining Beatles all took turns on the drums for some of the tracks. When Starr finally returned he found his drum kit covered in flowers.

15. The closest the Beatles came to reuniting was at Eric Clapton's wedding to Patti Boyd in 1979, where McCartney, Harrison and Starr played. Lennon did not attend.

16. The last time Lennon and McCartney played together was at the Los Angeles Hit Factory studio in 1974. The abysmal (and possibly drug-fuelled) session, which also featured Stevie Wonder and Harry Nilsson, was of such bad quality that the bootleg recording was released as A Toot And A Snore In 74.

17. Lennon and McCartney each recorded demos called India which remain unreleased. Each of them also recorded a version of Fats Domino's Ain't That a Shame for their rock and roll albums (called Rock 'n' Roll and Снова в СССР respectively).

18. The first song ever written by Lennon was called Hello Little Girl. McCartney's first was I Lost My Little Girl.

19. Lennon was charged with plagiarism by Chuck Berry's publisher over Come Together which resembled Berry's 1956 song You Can't Catch Me. The case was settled out of court. George Harrison faced and lost a similar lawsuit over his solo hit My Sweet Lord which resembled the Chiffons' He's So Fine.

20. Lennon's number 9 connection: Lennon was born on 9 October 1940, his son Sean was also born 9 October, 1975. He wrote the songs #9 Dream (part of Lennon's ninth solo album Walls and Bridges which was released in the ninth month of 1974 and peaked at number 9 in the US charts) and with the Beatles - One After 909 and Revolution 9. He lived in apartment number 72 on 72nd Street in New York and was killed in the evening of December 8 when it was already early morning of December 9 in his birthplace of Liverpool.