Sir Menzies Campbell will either be sacked or will end up in the Cabinet.(POLITICS)

There is just one consolation for Sir Menzies Campbell as he prepares for his second and probably last conference as Liberal Democrat leader: they will not come after him in Brighton. It is too late, now, to knife the leader. Gordon Brown could call an election at any moment, and there is no time for regicide. Sir Menzies has been saved by the sheer desperation of his predicament.

So much fun has been had blaming David Cameron for Labour's lead in the opinion polls that few have looked closely at where Mr Brown's new voters are really coming from. The Conservatives have, in fact, held on to their voters reasonably well. The Lib Dems, by contrast, have suffered an exodus. For years, the Lib Dem party has been used as a left-wing sanctuary for voters who could not stomach Tony Blair. Now he has gone, they are returning to the Labour fold.

If today's polls were tomorrow's …