Once upon a time, there was MerKozy -- the happy union of German Chancellor Angela Merkel and her darling little French President Nicolas Sarkozy. This center-right duo ruled Europe with an iron rod, espousing market-led reforms and the privatization of a new Europe.

Then in May, the beastly Mr. Francois Hollande won the presidency and ruined not only a catchy acronym, but the whole Franco-German love-in. The socialist upstart, after gathering a coalition of anti-austerity acolytes behind him, tore up Merkel's fiscal pact and challenged the hitherto unchallengeable orthodoxy of tax hikes, welfare cuts and reduced public sector spending designed to yank the eurozone from economic Armageddon.

The previously unassailable pair had been transformed from MerKozy to -- excuse my French -- MerDe.

And now British Prime Minister David Cameron has become the latest leader to challenge, and ultimately humble, the Iron Chancellor.

Cameron -- on an errand from Washington -- flew to Berlin on Thursday to express both his and President Barack Obama's fears that unless Merkel takes action to rescue the ailing economies of Greece and Spain, the euro zone has no future.

According to Downing Street, Cameron and Obama spoke [Read: Obama told Cameron], and the pair agreed on the need for an immediate plan to neutralize the growing threat of a messy breakup of the currency union.

Thursday's flight is designed to put pressure on Merkel ahead of next week's G20 summit in Mexico and the Brussels meeting of EU heads later this month.

The prime minister's view has always been that decisive action needs to be taken in order to underpin the eurozone, a No. 10 aide said.

And according to British Chancellor of the Exchequer George Osborn, Cameron will also tell Merkel speed is of the essence in restoring stability and market confidence in Europe and its currency union.

What's more, Cameron has even joined forces with Hollande in advocating euro bonds; the continent-wide scheme dreamt up by the French premier to promote growth throughout the union and allow the indebted nations to borrow at affordable rates.

Not only is Cameron daring to advise the German chancellor on how to run Europe, but he's telling her to hurry up about it, too!

Sensing the growing perception his visit is more of a lecture for the beleaguered chancellor, the PM has been keen to publicly downplay his role to that of a kindly advisor.

 I think all countries across Europe can help by offering the right advice and the steps forward to the eurozone countries, he said on Thursday.

I don't think it's right to try to lay all the responsibility on one person [i.e., Merkel]. It is everyone in the eurozone and throughout the EU.

However, the PM's uppity chiding -- don't forget Britain is not even in the euro zone -- will likely be seen as nothing less than an all-out attack on all fronts by the German public.

The jingoistic front page of Friday's German Tabloid Bild has, no doubt, just written itself.

So here we are again; France, Britain and the U.S. vs. Germany.

One can only hope the irony that yesterday was the 68th anniversary of the D-Day landings is not lost on the participants of this latest assault on Fortress Europe.