Why does it take a crisis to sting Cameron into action?

James Forsyth reviews the week in politics

The bar of the Brighton Metropole hotel was packed on Saturday night, with the sort of people locals would want to avoid. It was the Tory spring conference, and the journalists and aides were drawn to the bar not only by the prospect of doing a whole conference’s worth of drinking in one night but by news of a ‘seismic’ poll in the Sunday Times.