The Cameron-Sarkozy special relationship
In an ornate state room at Lancaster House, the leaders of France and Britain sat side by side and signed two treaties on defence and security.
On the surface it was like so many treaty signings: the asides between David Cameron and Nicolas Sarkozy about the pens, the handshakes and applause from French and British ministers occupying the front rows.
David Cameron spoke of President Sarkozy as "my good friend; a great leader and a good friend of this country".
President Sarkozy in turn said to the British leader: "I admire your courage, David, your vision and that of your government."
The claims made for this new era of military co-operation were ambitious.
After all, both countries in the past had attempted to work together. But Nicolas Sarkozy said the planned co-operation was "unequalled in our history".
David Cameron spoke of two world-class armed forces working closer than ever before.
The president said later that the fact that Britain and France had taken such a step was a historic event enabling both to make savings.
David Cameron described it as "a special relationship".
The scale of what is being attempted - from sharing aircraft carriers, to having a joint reaction force, to the testing of nuclear components - is different.
The need to trim defence budgets has brought both nations to this point although the expected savings have yet to be set out.
Both leaders, aware of potential domestic critics, claimed this was not about weakening their countries as powers.
As to the question of whether the French president would allow a French carrier to be used in some future conflict, say in the south Atlantic, he was elusive.
Mr Sarkozy said it would take a "hell of a crisis" for Britain to deploy its aircraft carrier. He couldn't imagine it would be done trivially.
He insisted that "our values are the same, our interests are shared".
It did not fully answer the question of what would happen if the two nations disagreed about the use of armed force which has occurred as recently as Iraq.
And what if there was a change of government?
The president said that both he and David Cameron saw beyond the democratic scan of their two governments. He said he relied on common sense. Britain was France's closest neighbour.
This partnership will underline that Britain and France are the two biggest military powers in Europe.
This agreement was not negotiated at European level but between two nation states.
Indeed President Sarkozy had a slight dig at Brussels. In reference to a question, he spoke of European Commission President Barroso or Council President Van Rompuy leading a French/British force.
He said that nobody could have that idea and he added that he was not in favour of "a plethora of bureaucrats".
Mr Sarkozy said he had had a number of frank exchanges with European officials.
On the question of the EU budget he said that when "my dear David" put the question of the budget on the table at the last Council meeting in Brussels we "both leapt at it", referring to himself and Angela Merkel.
He supported either an overall budget cut or a limited increase.
But he did not give any undertakings to support Britain keeping its rebate.
The French president recognised that the Common Agricultural Policy was not popular in Britain: he understood the British red-lines and promised only not to be confrontational.
The chemistry between the two leaders appears good.
A special relationship has been launched on the need to find spending cuts.
This is an entente cordiale that will be tested, as always, by events.
But two military powers also accepted today that alone they no longer have the means to project their power globally. They need to co-operate not at a pan-European level but as two national states with long military traditions.