So watch this space. It could be tonight.
UPDATE @22:55 - As if by magic
I know this is not a direct challenge, but I think it is what they call in the trade "feeling the water"
William Hill have installed David Miliband as 5/2 favourite to succeed Brown.
From the Observer:
Gordon Brown would be forced to appoint a deputy who could be swiftly groomed as his successor under humiliating last-ditch plans being discussed by ministers to patch up his failing administration.
Senior figures are holding emergency talks on ways to stop what one called the 'haemorrhaging' of power from New Labour amid signs that Brown is losing control of his party. Rumours swept Westminster yesterday that one senior cabinet minister has begun raising money for a potential leadership bid, while up to 40 backbench MPs are said to be ready to back a challenge.