What Clegg is thinking
Up until today, Nick Clegg has been very very careful to stick to a carefully drawn-up formula about how the Liberal Democrats would react to a hung Parliament - the party with the biggest mandate (a word carefully left undefined) should get the chance to govern; the Lib Dems were not interested in getting "bums on to the seats" of ministerial cars and would, instead, focus on delivering their four election priorities - a fairer taxes, extra help for disadvantaged children at school, a green economy and a fairer political system.
Today's interview with Andrew Marr marked the first shift from that. Clegg said that if Labour had the most seats in the Commons but the least votes (a possibility, according to recent polls) they could not govern:
"I think a party which has come third and so millions of people have decided to abandon them, has lost the election spectacularly, cannot then lay claim to providing the prime minister of this country".
In that case, unless there is a spectacular Lib Dem breakthrough, the assumption must be that Clegg would support - if not necessarily join - the Tories in forming a government. Nick Clegg's predecessor and adviser Lord Ashdown told The People today: "A coalition (with the Tories) is not an option for us. The parties are too far apart."
Coalition with one or other big party is clearly on the Lib-Dem leader's mind, though, as this exchange shows:
Marr: Could you sit round a cabinet table with David Cameron?
Clegg: I could sit around a cabinet table with anyone who agrees with me that what we need to do is hard wire fairness into the British... into the tax system.
Marr: Including Gordon Brown?
As I write this, I am aware that this is precisely the sort of "poll-based, what if" speculation that angers Gordon Brown. I'm told that Labour has asked the two other big parties to sign a joint letter to broadcasters criticising them for covering the debates and the polls too much and claiming that the news bulletins had "failed to deliver the usual specialist examination of specific policy areas". The Lib Dems and the Tories have refused to sign. The BBC has yet to receive the letter.
Update 1520: Labour now confirms that it talked to the other parties about sending a letter to broadcasters.
A party spokesperson says:
"We believe that an unintended consequence of the attention (the debates) get has been a lack of policy scrutiny and discussion that was normal in previous election coverage.
"We think the public are being short-changed by the focus on process not policy. Yesterday both of the other main parties said this idea had merit today they don't - that's tells you all you need to know about their enthusiasm for a policy discussion. They are the anything but policy parties."
This is the full draft of the suggested letter:
"To: BBC, ITV, Channel Four,
"If there is one thing which all parties can agree on it's that the televised leaders' debates have been a welcome development which has given a real sense of energy and excitement to the election campaign.
"However, as we reach the final stages of the campaign we also share a common belief that the focus on the debates, both the process surrounding them, and the polling before and after which they have attracted, has dramatically reduced the amount of airtime dedicated to the scrutiny of the policies of the parties. This is particularly so in the case of the main bulletins which remain the main source of news for many people.
"We feel that whilst our manifestos were fully, fairly and properly covered, since then the usual specialist examination of specific policy areas has not been done.
"We are writing to broadcasting organisations with a public service remit to ask you all to ensure that during the last ten days of the campaign your programmes analyse our policy proposals to the same level of detail as at previous election campaigns.
"If the public are not exposed to the different policy details and arguments which we are presenting we are concerned that you will not be fulfilling your traditional duty of explaining and probing the plans of all the main parties. If the public don't hear the arguments we believe that, despite the impact of the debates, many will still be in the dark as to the differences between our plans and values.
"We are copying this letter to Sky News."