A tremendous air of excitement here in Paris. Even before getting here, it was clear that French society is profoundly different from our own.

St Pancras International, boarding the Eurostar, all the staff are French. Every one of them that I encountered was going to vote, either in the London Borough of Camden or in Kensington.

There are, they claimed, 100,000 French voters in London, and they all expect to queue, as they did in the first round of the French presidential elections, for several hours.

But it’s not just France that’s voting today, but Greece and Serbia. The Serb election is interesting because it is the first in which the independence of Kosovo does not seem to have been an issue.

Greece foreshadows an unprecedented event in which the two parties that have dominated Greek politics for as long as anyone can remember, both look likely to be ground to electoral dust.

The extremes – the Communists and the extreme right wing – are likely to generate together 15-20 per cent of the poll, and a myriad small parties together are likely to produce a pretty anarchic outcome. An outcome that could send shockwaves through the eurozone and see Greece’s own departure from it.

Here in France, you have a straight right-left contest for the presidency, and plenty of personality to boot. And yet everyone you talk to here thinks nothing too much will change.

That’s not the view of the eurozonistas encamped in Frankfurt, who fear that if Mr Hollande wins he will follow up on his word to try to renegotiate the processes for reforming the eurozone itself.

On the lighter side, if he does win, Mr Hollande will become the first president of any country to be called by the name of another.

We shall be live in Paris, Athens and London tonight, and we’re on at 6.30. I don’t usually ask you to join us when I’m blogging, but today I do. It’s a moment of history for all our tomorrows.

It’s not often you want to start the day with far right French nationalist’s words ringing in your ears. But Marine Le Pen’s words after winning nearly one in five French votes in the presidential election have an eerie ring.

Ms Le Pen spoke of a people fed up with the “two main parties”; fed up too with paying the price for the “misperformance of the banks” with which she says successive governments have been in league with; fed up too, with immigration.

Does Bradford West speak of this? Hard to tell. But love him or hate him, the nature of George Galloway’s victory has not been seen in 50 years. Ms Le Pen’s 18 per cent in France is also without modern precedent. Both votes speak of discontent with the status quo.

Read more: Hollande edges Sarkozy in French election first round

But think too of Scotland. The wholesale demolition of the “two main parties” and their replacement by a nationalist party which was once as far out on the fringes of life as once was Ms Le Pen’s National Front.

If you add in the vote of the hard left in France – 11 per cent –  the two extremes in France polled together more than each of the other two main parties – 29 per cent to Hollande’s 28 per cent, and Sarkozy’s 27 per cent. Something is happening here and it is happening in a country very much more like Britain than Greece is.

Speaking of Greece, watch the case that Greek lawyers are taking to the International Criminal Court charging the “the two main parties” with genocide. I’m not suggesting the case has a cat’s chance, but it reflects the nationwide desperation in Greece with austerity, deprivation, and widespread emigration. Greece has a general election all too dangerously soon.

Sterling perhaps gives us a sense of detachment. Our borrowing rates on the markets are good. But our austerity regime also risks alienation. The belief, right or wrong, that “we the people” are paying the bankers’ price is widespread.

Strangely, the novelty of coalition politics may be disguising what is going on beneath the surface. We can hardly determine what is really happening by analysing one Galloway.

But the political classes in Europe are in trouble. France tells us the extremes are in play. No one knows what Greece will tell us. What will the Local elections in the UK tell us? Anything?  As the membership of the UK’s political parties plummets, is London happy with a Mayoral choice that comes down to “the two main parties”? Don’t yet hold your breath for a Green or Independent breakthrough.

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For the last years of Labour’s time in power, bilateral summits between France and Britain became a commonplace. At the last one between Gordon Brown and Nicolas Sarkozy, the French offered a deal to share aspects of their nuclear deterrent – submarine patrols that would reduce the need to have so many Trident Subs, and warhead maintenance.

Mr Brown emerged saying that an Anglo-French deal that compromised the integrity of the “independence” of the nuclear deterrent would be politically undeliverable.

But sources both sides of the Channel have told me recently that David Cameron is actively interested in rendering such an agreement more than politically deliverable.

A couple of weeks ago a senior French Government source told me to look forward to the next Anglo French summit with considerable anticipation. There’s “something very big to be announced”, he told me.

Today’s FT begins to put some more flesh on the bones, suggesting that French nuclear technicians may be engaged in maintaining the UK’s nuclear warheads. The article points out the considerable concessions the US would have to make, effectively to allow the French in on US nuclear secrets.

There’s little doubt that the Brits are desperate to reduce costs on Trident. In my interview this week with Mr Cameron he told me that “we have already been able to make considerable savings with our nuclear deterrent”.

The idea that two allied European Atlantic powers have required totally independent submarine cover (bearing nuclear weapons) has for some time seemed something of an anachronism. My contact told me that Sarkozy’s idea had been for joint patrols which would reduce the total number of nuclear capable boats and missiles in both countries.

Watch this space. Is a UK Prime Minister, formerly regarded as something of a Euro-sceptic about to take what many might regard as a radically European step?

It is hard to overstate what an extraordinary event the appearance of the joint Brown-Sarkozy article in the Wall Street Journal represents. It is a most remarkable development.

Two politicians, technically coming from opposite sides of the political spectrum, coming together to forge a significant and powerful attack on the global banking and energy speculating system.

Two leaders from two nations with economic and cultural clashes in their backgrounds that are amongst the most lampooned in Europe. Why, it’s only little more than a week since they were supposed to be at loggerheads over who had won what in the disbursement of high level posts in the EU.

Yet here they are, singing from the same hymn sheet on a day after the UK chancellor attempted the first serious tax hit on bank bonuses.

And make no mistake, this is a less than veiled acceptance by Mr Brown that the German attack on the Anglo-Saxon financial model was justified. So this will go down incredibly well in Berlin too.

This may also represent a rallying point for Democrats in America, disenchanted with the way the banking system there has used taxpayers’ money to recover and return to the opaque ways of remunerating itself to extreme levels from producing very little.

Bankers using taxpayers’ money to fatten their war chests and their wallets at the expense of NOT lending to those who actually DO make something, represents one of the continuing scourges of the post-crunch world.

In so many ways too, the Brown-Sarkozy alliance in all this flies in the face of so many media stereotypes.

The thought of energy-rich France, which profits so considerably from energy-strapped Britain’s needs, actually siding with us in the face of energy speculators also represents a fascinating first.

The article is likely to serve as an intriguing watershed which is likely to prove a reference point for a good bit of time to come.

It certainly renders today’s G8 meeting in Italy suddenly rather interesting. And if bankers think they can shunt their ill-gotten gaming activities elsewhere, it is beginning to look as if we may actually be seeing the seeds of an international action to block them.

Wellington and Napoleon must be spinning in their graves, let alone Harold and William the Conquerer!

I’m sitting the Locarno room at the Foreign Office waiting with 200 other hacks for the Obama/Brown press conference, and even in this august circumstance there’s an air of a palpable expectation.

Not of course in terms of economic breakthrough but the mere arrival of The Man.

There are American and British flags entwined on the base in this English Imperial pile, and everybody awaits with some anxiety the arrival of what is called the “travelling White House press corps”.

They are notoriously assertive and will come crashing in, seizing our preciously reserved seats. Some of us have been here since dawn.

As for content, everyone is talking about Sarkozy’s threat to walk out if there isn’t a global regulatory deal. And others are talking about Brazil’s President Lula coming here by train from Paris.

He will change trains at Stratford East, and some are jesting that he will see few white faces with blue eyes (those that he has blamed for the pickle we are in).

To watch live coverage of Barack Obama’s meeting with Gordon Brown, plus the protests in the City of London, click here.