Matthew d'Ancona was spot on in his piece for last night's Standard. The TV debates have changed everything; a politician who hasn't been through the wringer of the televised debates has no legitimacy to lead the nation. This also explains Salmond's panicked legal challenge; the next PM will also be recognised in Scotland as having greater legitimacy than Salmond, who will remain a regional boss in the United Kingdom rather than the leader of the Scots nation.
Since Clegg has ruled out Brown, this effectively condemns Labour to having to agree to Clegg as PM in any Lib - Lab coalition; the public just won't accept Johnson or any of the others waiting in Labour's wings, simply because they weren't part of the debate.
What interesting times these are.