Until recently, we have all assumed that there are four possible outcomes of the current talks: a Lab-Lib coalition, a Con-Lib coalition, a "confidence and supply" arrangement beween the Tories and the Lib Dems, and a minority Conservative government.

We can now remove the last of those options from the list. George Osborne has just become the first senior Tory to rule out a minority government.

In an interview on the Today programme, he said:

I keep reading about this option and I'm afraid it doesn't really exist. We can't just turn up at Buckingham Palace and say we'd like to form a minority government. We would need the consent of the Liberal Democrats to form a minority government.

Osborne's remarks confirm that the Lib Dems will have to strike a deal with either Labour or the Tories. There is no walking away.

Now, this may just be a negotiating position, but the arithmetic is still against the Conservatives. A Tory minority government, assuming the support of the Democratic Unionist Party, could muster 315 seats in the Commons. Excluding Sinn Fein, that would leave it six seats short of a majority. The Conservatives could be voted down regularly by the progressive majority in the House and would struggle to pass Osborne's planned emergency Budget.

It is hard to imagine the Tories, so fond of "the smack of firm government", entering power on these terms.

Special offer: get 12 issues of the New Statesman for just £5.99 plus a free copy of "Liberty in the Age of Terror" by A C Grayling.