James Humphries knows a thing or two about politics and presentation, having - reportedly - sat across a desk from Alastair Campbell when he was as a strategy advisor to Tony Blair.

Now, as Green Party candidate for the London consituency of South Islington, he gives an insider's view of how decisions are really made. Here's a money quote from yesterday's Guardian:

Like others, I did wonder why we had to wait two years for a white paper on sustainable development when the Bank of England could be given its independence within a week. The reality was that the environment did not then have enough "saliency" to be a true priority for New Labour.

"Salient" issues, in Downing Street jargon, are those that voters (especially in marginal constituencies) say matter most to them. If crime or asylum emerges from polling and focus groups, then politicians respond with speeches and initiatives. Anything that is not a salient issue can languish.

Caspar Henderson