I would have put a fair amount of money that The Lovecats was the holder of that title, but it only scratched its way to #7 in 1983, although I'm guessing that it in fact outsold Lullaby.
And even if you told me that the biggest success wasn't The Lovecats, I'd have then place whatever was left of my cash on Friday I'm In Love, but this only swooned its way to #6 in 1992.
So the best performing 45 turns out to be the one about the creepy and haunting tale of an eight-legged creature that frightened Robert Smith is in his nightmares as a youngster. Or, is in fact the song, as has been suggested in some places, really about drug addiction and dependency but written in such a way that it gets past the censors at the BBC for the all important airplay?
Either way, I think its one of the most inventive arrangements to feature on any record by The Cure, and I've dug out the 12" single from the cupboard for you all to enjoy once more along with two rather decent b-sides:-
mp3 : The Cure - Lullaby (extended mix)
mp3 : The Cure - Babble
mp3 : The Cure - Out Of Mind
And here's the very memorable promo:-