In the two-page typed draft with handwritten notes, Lennon criticises the couple for their treatment of him and his wife, Yoko Ono.

The attack is said to be in response to Linda's criticism of him not publicly announcing his departure from the band.

The letter was sold at a US auction to an anonymous collector in Dallas.

The opening paragraph makes reference to a letter Lennon received which he said made him wonder "what middle-aged cranky Beatle fan wrote it".

He said: "I resisted looking at the last page to find out—I kept thinking who is it—Queenie? Stuart's mother?—Clive Epstein's wife?—Alan Williams?—What the hell—it's Linda!"

Lennon went on to respond to accusations he was "self indulgent" by criticising the couple for their treatment of him and Yoko.

Using strong language, he said he hoped they realised the trouble "you and the rest of my 'kind and unselfish' friends laid on Yoko and me, since we've been together".

'God help you'

Making direct reference to his former bandmate McCartney, Lennon questions the notion that "today's art" came about because of the Beatles.

He wrote: "I don't believe you're that insane - Paul - do you believe that? When you stop believing it, you might wake up!"

He also responds to the criticism that he did not publicly announce he was leaving the band, saying he was asked by Paul and former manager Allen Klein to keep quiet as it would "hurt the Beatles".

In his last attack directed at Linda, he says he suffered because of her "insane family/in laws" before adding in capitals "God Help You Out, Paul".

US auctioneers RR Auction said it believed the letter was written around 1971 - a year after McCartney publicly announced he was leaving the band.

It said the letter, which sold for $29,843.45, "captures the intense rivalry between the two men in the months, and even years, surrounding the break-up of the Beatles".

(BBC)