Sometime today, in a conference room in Berlin, David Cameron will indulge in a certain amount of spleen venting. No doubt a little tapping pointedly on the table will take place. Who knows, maybe he'll even advise his interlocutor to "listen to the Doctor dear".
And then with a bit of luck, Angela Merkel, bedecked in Lincoln Green, will lean over the table, and whisper "But David. I thought we were all in this together?"
What will have brought all this unpleasantness to pass? Why it's that new favourite wheeze of German and French politicians: the Tobin Tax.
Now, the Tobin tax is that strangest of beasts, a popular levy. One that the public would welcome with open arms. So how come we have the German Chancellor offering to take from the rich to give to the poor, while Cameron, Osborne, Balls and Cable all scramble to play the Sheriff of Nottingham, shouting "no, no, no"?
When all three major parties pass up the opportunity of a populist open goal, you know there must be more to this than meets the eye. And there is.
Firstly - and it would be easy to miss this -- the Lib Dems, Tories and Labour are all actually in favour of the Tobin tax. Everyone thinks it's a grand plan. Just not right now. And not in the form the Merkozy axis has proposed.
"Give me a Tobin tax and fiscal continence. But not yet," they are saying, in a St-Augustine-sort-of-a way.
So what's the problem?
Well the financial implications to London have been extensively written about already.
But there's another issue: French farmers.
Of course, it's not just Normandy cheesemakers and the like. It's every other thing the EU spends money on -- though with large parts of the total EU budget going on the Common Agricultural Policy, French farmers are set fair to do well out of an EU wide Tobin tax.
How come? Because as things stand, revenue raised from The City of London would go, not to the Treasury, but to Brussels. You can write your own Daily Mail headlines, can't you? I expect Paul Dacre already has.
And that's the nub of the problem. With 70 per cent of its potential revenue coming from the UK, even the most pro-European British politicians fear that the Tobin tax, excellent idea though it is, may prove rather less popular with the British public when they see what the money is being spent on.
Because given the state of the Eurozone, Angela Merkel knows we're all in this together. But some of us are in it rather more than others.
Richard Morris blogs at A View From Ham Common, named Best New Blog at the 2011 Lib Dem Conference.