+++ Purnell resigns +++

James Purnell's resignation today, we are told, came as a surprise to Downing Street. The Prime Minister apparently took soundings from Mr Purnell as early as this afternoon and the good ship Brown (are ship metaphors being overdone?) was happy with the reply of the Work or Prisions Secretary.

His resignation should not have been a surprise, and yet it appears to have been.

Talk tonight of further resignations, John Hutton, Andy Burnham and even David Miliband would undoutedly change the picture dramatically, if they occured. The change would to to such an extent that it would be impossible to see how Gordon could continue.

In short, what we are witnessing is a cabinet coup.

But, like any coup, you shall need enough support. If Miliband, retaining if Foreign Office position, comes out and supports Gordon then I suspect the immediate danger shall pass.

However, one thing which shall be undoutedly damaged is this. Only three days ago the immending cabinet reshuffle was billed as being 'radical', Chancellor Balls, Foreign Secretary Mandelson etc. If, and this is still a hypothetical if, Darling and Miliband remain in their positions it shall demonstrate something much more dangerous - Gordon is scared.