Re-raise the flop. The only hands you're behind to are AA and JJ, and he is very unlikely to have either of them, if if he did, surely he'd wait til the turn before raising and therefore smooth call your flop bet. To check-raise on an ace high flop which he has raised preflop is odd, and it's hard to think which hands he might do that with. Therefore re-raising is a must, you don't have a totally clear indication on his hand.
Well, because I didn't think he had AA or JJ, I smooth called his preflop raise. I thought he had something like AQ or AK and didn't want to lose my customer. If a blank comes, then I should be able to extract some more dosh. If I reraise the flop, then he's gonna realise that I'm not messing around.
Unfortunately, the king came on the turn.