It was all banter, mate.
Cameron declared that he was only joking when he accused Michael Meacher of being on mind altering substances. Something the PM and Chancellor would know all about.
Dave admitted he smoked pot and has never denied taking cocaine, even when he was asked whether he took it after he was elected. When asked by Alex Thomson of Channel Four News, all he confirmed was he hadn’t snorted since 2001:
AT: “If you were asked have you ever taken class A drugs as an MP, would you answer that question?”
DC: “I have always said that lawmakers cannot be lawbreakers. All I have said about my past, though, is that what is private in the past should remain private.”
AT: “If I asked you if you’d snorted cocaine as an MP, you’d therefore say No, wouldn’t you?”
DC: “That’s right, but please, I mean, I think we’ve dealt with this issue…”
AT: “So that’s ‘No’?”
DC: “I’ve absolutely answered your question.”
AT: “Say No.”
DC: “I’ve just said No.”
AT: “Thank you. Right. We can move on.”
That’s a rather extended “normal university experience”.