In a country of 60 million inhabitants, a group of one million, no matter how vociferous, does not constitute a majority. I suspect that at least as many, and probably rather more, actually supported the Labour Government's decision to go in with the USA, they just didn't organise a 'Hell Yes' march to show that support.

Not making a judgment on the rights and wrongs here - just looking at it with the logic of a politician. A million said "No", 59 million said nothing, and to a politician I guess that's the same as saying "Yes".