But once a year or so the leash is loosened, and the Government indulges its backbenchers - and indeed cabinet ministers - by allowing them a "free vote". Which means that they are permitted - without fear of excommunication, loss of privileges or expulsion from that meaningless junior ministerial post - to vote the way their conscience (or sense of political self-preservation) dictates.
The Divorce Bill on Wednesday night was such an occasion. Other recent free votes have been over capital punishment, Sunday trading and abortion rights. These are "matters of conscience", where (so the legend runs) it would somehow be indecent to coerce members to vote against their deeply felt principles.
And they are odd bedfellows. I can see why the question of whether the state has the right to take life is a matter which causes real personal anguish. But the length of the cooling-off period for divorce cases? Are there really groups of Britons who shout, "give us eighteen months, or give us death!"? (Aside from Anne Widdecombe, that is).
And why is this allowance for conscience so selective? Will those of us embracing shamanism be given free votes on transport policy, so as to protect the spirits of trees, rocks and pools from the road-building programme? Is not the question of, say, alleviating poverty a "matter of conscience"?
In the case of the Divorce Bill the suspicion has been all along that the Government - taken aback by the scale of opposition to its proposals on its own benches - agreed to a free vote, calculating that Opposition MPs would ensure that it passed unamended. But on Wednesday night they didn't.
So when the Prime Minister arrived for Question Time yesterday he looked weary and fed up. Dame Jill Knight (a keen eighteen monther) tried to make it up to him. In a soothing voice she praised his stance on landmines and urged him to use "his considerable influence to achieve a worldwide ban". He thanked her in hollow tones, perhaps wondering why Dame Jill thought he could talk the Chinese Red Army out of using landmines, but not persuade the Home Secretary to support the Lord Chancellor.
Over the divorce fiasco itself he had only one strategy open to him - The Good Loser. Which ran roughly thus: great debate; finest traditions of the House; best side won; no hard feelings. This England soccer manager approach cut no ice with Killer Blair. It was yet another example of the Government's feeble, faltering, incompetent, humiliating, divided, decaying and generally not very good state. Cabinet members voting against one of the government's very own measures. The shame!
"Aha", said Major, would Mr Blair not allow cabinet ministers to exercise a free vote, then? This was "the new, autocratic Labour party. If someone strays a signed statement of retraction is put out in their names the same day". Labour bottoms on benches behind the Great Leader shuffled uncomfortably. It was a palpable hit.
But it was something else that worried me. As some Conservatives noisily pointed out, the Labour leader and many of his colleagues had failed to register any vote at all on the lost amendment. "Now this is a novel constitutional proposition", rejoined Blair, "that I should turn out to help save the Government from its own cabinet members!" Yes, Tony, nice party political point. But who then is to save the rest of us from the peculiar consciences of the Moral Minority? We do not get free votes.Reuse content