The Tea Party across the Atlantic are such a scary bunch that even other Republicans are loathe to include them in mainstream and front-line politics. The British example here isn't anywhere near as extreme - you don't see any of them questioning David Milliband's birthplace for example - and as a left-winger I would say it is even very understandable why they are doing what they do. There is nothing redeeming about the American right whereas the British right have their reasons steeped in logic and rationale, even if it is in a completely different direction to the left.