Paul McCartney in an interview with Paul Gambaccini, December 1978:
(transcribed by Gareth Bramley)
" I was asked to write Diamonds Are Forever. Somebody I knew was connected with the Bond thing and said 'would you like to do a song' and I said 'Yeah!!!! (straight away, you know, YEAH!!!)
I couldn't do that one coz I think it was John Barry and they had it all sewn up anyway, so maybe (you can do) the next one. "