He can refuse to pay, as has been said. The Eurocrats have said that they will then fine the UK. They keep fining France for various things and France pays if the fines are less than the cost of compliance, otherwise I'm told that they don't pay the fines either!
I don't think they'd throw us out until it had dragged on a long, long time, but they just might make an example of us. You'r right, it would certainly save the cost of a Referendum!
Didn't I read somewhere that Holland was mounting a legal challenge?