Lord Barnett's formula acquires a new floor every day

Lord (Joel) Barnett, whose spending formula remains controversial after his death

Three questions for you. Who's in favour of fair funding?

Yes, I thought so. Ok, so who's in favour of unfair funding? I thought so.

A trickier third question: what is "fair funding?"

Labour's UK manifesto, published today, promises "a fair funding settlement for Wales, with the guarantee of a funding floor."

The party says: "The next Labour government will introduce a Barnett funding floor and deliver fair funding for Wales. For Labour, it is a point of principle that all parts of the Union should be fairly funded, not a political bargaining piece, and will act to put this in to practice."

There are no details in the manifesto of how much the Barnett floor would be worth in terms of actual money. Perhaps we'll find out more when Labour's Welsh manifesto is published later this week.

The Liberal Democrats repeated their commitment to "fair funding" at the weekend, promising: "We recognise that the current Barnett formula underfunds Wales. We will address this imbalance by entrenching a Barnett floor set at a level which reflects the need for Wales."

The Lib Dems say they will commission work to update the analysis of the Holtham Commission and - after the update - "we will then seek [my emphasis] to increase the Welsh block grant to an equitable level."

'Better funded'

What would the Conservatives do? Chancellor George Osborne has promised negotiations with the Welsh government over the funding settlement, but - like other politicians - could not yet confirm the exact level.

He said it had "clearly got to be in the range" set out by economist Gerry Holtham, who said Wales should get between £113 and £116 of public funding per head for every £100 spent in England.

"Wales would always be better funded than England," said Mr Osborne, although as the current figure is £115 Wales should clearly not expect a great windfall.

If the Barnett formula had any more floors it would need planning permission. I suspect many voters in England may have a different definition of "fair funding" but the enthusiasm for a Barnett floor among the UK-wide parties isn't shared by Plaid Cymru.

Plaid's Ian Johnson said: "A Barnett floor does not offer a lasting solution, and if austerity continues then a Barnett floor will not generate any additional resources for Wales at all. At best it will stop the situation getting worse; it will not make the situation any better. It will not give Wales fair funding."

Unusually in the world of fair funding, Plaid Cymru have put a price tag on what they want - £1.2bn - but no party likely to provide the prime minister and chancellor is prepared to deliver it.