So Vince Cable won't be the next chancellor after all. Today's Guardian  reports that the Liberal Democrats are planning to rule out forming a coalition government with either the Conservatives or Labour in the event of a hung parliament . But they will be prepared to offer parliamentary support to any party that accepts their "shopping list" of four demands.
So who, as things stand, would pass the Clegg test?
1. "Investing extra funds in education through a pupil premium for disadvantaged children."
Conservatives: The Tories have already promised to introduce a pupil premium, with extra funding for schools that take children from the poorest homes. But the party has yet to say anything about how much it would spend, or where the money would come from.
The Lib Dems have said that the policy would cost £2.5bn a year, with the average school receiving roughly £2,500 extra for every disadvantaged child on its roll.
Labour: Ed Balls opposes a pupil premium, arguing that it would not guarantee that pupils with disadvantages or extra needs actually get the support that they need.
Verdict: A point to the Tories. None for Labour.
2. "Tax reform, taking four million out of tax and raising taxes on the rich by requiring capital gains and income to be taxed at the same rate."
Conservatives: A number of Tories are impressed by Nick Clegg's plan to raise the income-tax threshold to £10,000, but David Cameron has yet to poach the idea. Instead, he plans to focus on cutting inheritance tax and recognising marriage in the tax system. In addition, George Osborne has pledged  to reduce corporation tax from 30 per cent to 27 per cent. The Tories have no plans to raise capital gains tax (CGT).
Labour: No plans to cut income tax, but Alistair Darling is said to be  looking at raising CGT in the Budget to stop the wealthy exploiting a tax loophole by declaring income as capital gains. This would please the Lib Dems, who could claim to have led the agenda.
Verdict: In anticipation of a rise in capital gains tax, Labour wins half a point.
3. "Rebalancing of the economy to put less emphasis on centralised banking and more on a new, greener economy."
Conservatives: Osborne is sympathetic to calls to split investment and retail banking but has stopped short of calling for a complete separation. Cameron has promised  a "localist green revolution" with companies such as Tesco and Marks & Spencer helping to make homes more energy-efficient. But will his backbenchers stand in the way? A ConservativeHome/ConservativeIntelligence survey revealed that reducing Britain's carbon footprint was the lowest priority  for Tory candidates.
Labour: The government has so far refused to separate retail from investment banking and is unlikely to change its position. On the "green economy", Labour has promised to create a more than a million new green jobs and to cut UK greenhouse-gas emissions by 34 per cent by 2020.
Verdict: Half a point to the Tories on banking and half a point to Labour on the green economy.
4. "Political reforms, including changes to the voting system and a democratically elected Lords, that go further than proposed by Labour."
Conservatives: The Tories are opposed to any electoral reform and support the current first-past-the-post system. Cameron opposes proportional representation on the grounds that it hands power to the "political elites".
The Tory leader has said he supports a largely elected second chamber but is reluctant to challenge his own peers on the issue, as they are opposed to reform. In private, Cameron has described Lords reform as a "third-term issue".
Labour: Supports the replacement of first-past-the-post with the Alternative Vote and has passed legislation to ensure a referendum will be held. The Lib Dems support the move as a "step in the right direction", but are disappointed that Labour did not opt for a proportional system.
The government continues to favour a predominantly elected Lords. However, Jack Straw has warned  campaigners that they will have to wait more than decade before this is achieved.
Verdict: Half a point to Labour.
Final score: Conservatives: 1½ out of 4
Labour: 1½ out of 4