One problem with the parliamentary system, at Holyrood and in Westminster, is that it tends to give too much power to political parties.

The whipping system actively undermines the likelihood that MPs and MSPs will act as individuals with distinct and varied views – although just that sort of independence is surely one of the principal advantages of representative democracy.

Part of me was heartened, therefore, to see Mark Pritchard, the backbench Tory MP for the Wrekin, resisting Government pressure to withdraw a Bill last week. He claimed that he had been first offered a job, and then threatened by the Prime Minister’s office, to get him to drop his motion to ban wild animals in circuses. “I am not going to be kowtowed by the Whips or even the Prime Minister on an issue I feel passionately about,” he said.

Since kowtow as a verb is intransitive, this was a clumsy construction, but not so mangled as to render his meaning wholly opaque. “We need a generation of politicians with a bit of spine, not jelly,” Mr Pritchard continued, ignoring the inconvenient fact that you need a spine to kowtow, and choosing instead to stress that he was positioning himself in the vertebrate rather than the medusozoic camp.

I back Mr Pritchard and his spine. But only up to a point. Unfortunately, we need a generation of politicians with brains even more than one with spines. It is here – from the occipital bone upwards – that Mr Pritchard, so plausible on the back front, fails to convince.

He seems not to have thought very deeply, for example, about what it means to be a Conservative. It’s a tricky question, but one need not be Edmund Burke or Michael Oakeshott to conclude that it isn’t about introducing more regulation, increasing the state’s power, and telling people how to behave. And it certainly isn’t about devoting parliamentary time, during the worst financial crisis in years, to an attempt to introduce blanket bans, especially one which would affect just 39 animals in England and Wales. (No circuses with animals currently tour in Scotland, but one has suggested it would rehouse the elephant it has owned for 50 years in Ayrshire if the ban is introduced in England.)

Above all, Conservativism is pragmatic. It takes account of reality and evidence. Separate reports, for the RSPCA and for the Westminster Government at the time of the last Animal Welfare Act in 2006, concluded that there was no evidence at all that animals kept by circuses are any better or worse off than those kept in any other form of captivity.

But it is invidious to single out Mark Pritchard for criticism. Amazingly, almost everyone who spoke in Thursday’s debate –Andrew Rosindell, the Tory MP for Romford, was the exception – was eager to support this peripheral, illiberal and illogical motion, which was nodded through without a vote. That does not mean it will become law south of the Border, but it does put pressure on the Government to bring forward legislation.

The ovine consensus on circus animals shown in Westminster is based entirely on inchoate sentimentality. There is a logical argument to be made for animal rights, most coherently expressed by Professor Peter Singer, the Australian utilitarian philosopher whose book Animal Liberation popularised the idea of “speciesism”. His conclusions, based on the proposition that the differences between human beings and other animals are merely those of degree, suggest that human rights should be extended to other species, the great apes should be represented at the United Nations, farms, zoos, meat-eating and leather should be outlawed and all aspects of animal husbandry abandoned. There would be no logical basis for distinguishing between the rights of a person and those of a shrimp. One suspects that this theory doesn’t have widespread support.

Of course, it’s not necessary to support all those ideas to oppose animal cruelty. But if there is no evidence (and there isn’t) to suggest that animals in circuses are treated cruelly or, at any rate, that their treatment differs from that of animals kept in zoos, safari parks, for other theatrical performances, or in your own house, what is Mr Pritchard’s motion based on?

If it is intrinsically cruel to keep animals in captivity, not only circus animals, but zoos, farms and ownership of pets should be outlawed. The same is true if what is wrong is that these animals provide entertainment; I find my cat Otis very entertaining. And I like watching Westerns, which would be impossible to produce if horses were not allowed to perform.

If what is wrong is that the animals are trained, this is also true of training dogs. No doubt the motion’s supporters would argue that domestic animals, such as cats and dogs, are different. But if it is the wildness of the animal which is the significant factor, what makes the animal wild? Many circus animals (and for that matter, those in zoos) are bred in captivity and trained from an early age.

The very fact that they can be trained makes it difficult to argue that there is something artificial about training a tiger, but not about training a cat. Elephants, for example, have been trained to work for thousands of years. There is no rational distinction between an elephant and a Clydesdale if working animals are acceptable at all.

There is no evidence of intrinsic cruelty, no rational distinction between circuses and zoos, and no logical objection to animals being trained and performing which would not apply to animals in films or TV adverts, or your own pets. So opposition to circus animals can only be expressed (as it was by MPs) by noting the exotic nature of the animals and vague anthropomorphic sentimentalisation.

According to one report, 92%of the public agrees with this motion. If that is true then, not for the first time, 92% of the public is wrong. Mr Pritchard unwittingly sums it up when he says “feels passionately”. The reason the Government disliked his motion is that legislation should involve careful thinking, not just passionate feeling.