U2 star Bono has been slapped with a no-coffee rule by his bandmates when they're working on new material, because he becomes difficult to deal with when he's consumed caffeine.

The Irish rocker accepts even he knew he was sometimes tough to be around after drinking the pick-me-up.

The Beautiful Day icon tells music magazine Rolling Stone, "You can imagine how annoying it is to have someone like me come in with a head full of big ideas."

But Bono admits there are times the group come to blows over ideas, especially when supercritical LARRY MULLEN fakes total boredom.

He reveals, "He's bored most of the time. You could be singing your heart out, and he'll yawn. But his instincts are 80 per cent right. If you're in the 20 per cent, it hurts."

And Mullen's fellow bandmates also have insensitive ways of letting the frontman know his latest idea is not one of his greatest.

He adds, "ADAM (CLAYTON) will fall asleep; EDGE will make some kind of remark about the chord changes."