Is there a Cabinet minister?

There are rumblings in Westminster that a Cabinet minister is preparing to join Hoon and Hewitt in calling for a secret ballot on Brown’s leadership.  H&H are claiming, quite laughably, that this whole process could actually strengthen Brown’s position.  But ministerial involvment would clarify, beyond doubt, that this is actually a rebellion designed to weaken Brown.  After all, this is hardly the kind of thing which falls under the banner of collective responsilbity…

The question now is: who, if anyone?  Obviously, the bigger the name, the more destabilising it would be.  Indeed, you feel that a Big Name might be required to give this sufficient momentum.  Could it be Tessa Jowell?*  Or might it be someone closer to the PM?  The thing to really keep an eye on is any action taking place off the radar.  This could be the kind of opening that Johnson, Miliband or Harman have been looking for.