h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

...Was not, in fact, given in a press conference. It first appeared in an interview Lennon gave to journalist Maureen Cleave, published in the London newspaper "Evening Standard" on March 4 1966.
Lennon's exact words, as quoted in the "Evening Standard", go like this: "Christianity will go. It will vanish and shrink. I needn't argue about that; I'm right and I will be proved right. I don't know which will go first - rock'n'roll or Christianity. Jesus was all right but his disciples were thick and ordinary. It's them twisting it that ruins it for me."
In the "Evening Standard" article, Cleave follows the quote by saying of Lennon: "He is reading extensively about religion." Later, she lists some of the unusual possessions she sees around his home. They include: "...a huge altar crucifix of a Roman Catholic nature with 'IHS' on it" and "...an enormous Bible he bought in Chester."

D'OH! That was clever of me - typing out the quote and missing six key words!
OK, Take 2. What JL said was this:
"Christianity will go. It will vanish and shrink. I needn't argue about that; I'm right and I will be proved right. We're more popular than Jesus now; I don't know which will go first - rock'n'roll or Christianity. Jesus was all right but his disciples were thick and ordinary. It's them twisting it that ruins it for me."
Incidentally, my source is an excellent book of writing about Lennon and The Beatles: "The Lennon Companion", edited by Elizabeth Thomson and David Gutman, and first published by Macmillan in 1987.
As well as the full Maureen Cleave interview, it includes a lovely piece about Lennon by the jazz singer George Melly, written just after Lennon's death.
Melly observed: "The sheer bulk of his obituaries is mysterious, beyond logic. Nothing he hoped for came about; wars rage, people hate, a young man buys a gun and waits outside the Dakota building; and yet everyone, it seems, feels diminished by his death."
I know I certainly did.