“I don’t mind a parasite,” says Humphrey Bogart in Casablanca, “I object to a cut-rate one.”

That may not be precisely the right quotation for my subject. The Groucho Marx comment, “I don't care to belong to any club that will have me as a member,” isn’t quite right either but is maybe closer.

Clubs have rules. Members accept the rules because they feel the benefits of membership outweigh the limits the rulebook imposes on them. For example, if you want to trade with the European Union, one of the hugest trading blocks in the world, you have to accept its rules. Indeed, even non-members have to accept a great many of them: Norway, for instance, which obstinately remains outside the EU, can only trade with the members if it accepts the regulations it demands.

Even more powerfully, the United States imposes its laws on the rest of the world, which accepts them, however grudgingly, because the alternative means exclusion from the world’s largest market. In more than one non-US company, I’ve had to commit to respecting US regulations on data confidentiality or standards laid down by the Food and Drugs Administration. It wasn’t a problem, because I agree with the regulations. Even so, there’s no doubt that while it may not represent taxation without representation, it is certainly legislation without representation.

This makes the debate in Britain about the European Union particularly curious. We are currently members. That means we have to accept its rules but, on the other hand, we have some say in making them. Leaving would mean a huge loss of influence in the organisation that most affects how Britain makes its living.

For all that, there’s a powerful head of steam today to take us out. That would move us into the position of Norway: subject to the rules, at least as far as trade is concerned, but with no voice over them.

Many would prefer that status. They feel that to be out would give Britain back control over many aspects of national life which it does not control today. Most powerfully of all, it is felt that it would give the country back the authority to prevent what is perceived as excessive immigration: currently, anyone from a fellow EU-member state has automatic residence and employment rights in Britain.

Indeed, that has been the focus of the debate for many months now. Give us back our borders. Keep out all those immigrants who are coming over to take our jobs. Or more to the point, not to take our jobs but to take our benefits.

See how the thoughts progressed, from one to the next? We started talking about sovereignty. We ended up talking about benefits.

And, indeed, David Cameron, in trying to persuade critics that he has done enough to give authority back to London, has focused on little else. To keep immigrants out, he wants the power to reduce benefits. Wha has he achieved? EU members seem open to the notion of an “emergency brake”, allowing a nation to stop paying benefits to new arrivals. However, it would only be applied if their numbers were such as to drive the benefits system into crisis. And only with the agreement of the other members.

Donald Tusk, President of the European Council
With only a little bit to give away to keep Britain in

As one Tory critic of the plan, Nigel Evans MP, pointed out “if we have to phone a friend, indeed in this case 27 friends, to decide that we can put our foot on the brake, then no driver in their right mind would get into a car.”

So we now have David Cameron trying to persuade his critics that he’s won a good deal, while they proclaim he’s done nothing like enough. And it all comes down to whether the British government can refuse benefits to people. The right to deprive people of help is the acid test of membership of the EU.

A great question for the future of Britain, whether or not it will remain in partnership with the other nations of its continent, seems set to be decided on the basis of nickel and dime bargaining.

It seems Cameron’s not at all sure whether he wants to be a member of a Club that isn’t letting him be enough of a cheapskate. Which must be pushing that Club into wondering whether he’s much more than a parasite. Though it can’t be in much doubt that he’s a cut-rate one.