Together with Bastille Day and the anniversaries of the end of the two world wars, today is a seminal date for France, reflected in the visit of President Nicolas Sarkozy to London for anniversary ceremonies and a plethora of celebrations on both sides of the Channel. It also raises intriguing questions about the Franco-British relationship, Europe, transatlantic links – and the legacy of the greatest French leader of the 20th century.
Charles de Gaulle's call on the BBC from London on this day in 1940 to his country not to give up the fight against Germany marked a historic moment, which salvaged French pride in subsequent years despite the way France had crumbled in the face of the Nazi assault. Far fewer people rallied to the Resistance, at least in its earlier stages, than was suggested by the subsequent myth that the country came together against the invaders with whom the Pétain administration signed a humiliating armistice on 22 June.
The broadcast was heard by few people in France, and the BBC did not keep a recording of it. He was virtually unknown in London and the British government, which had initially vetoed the speech, sought other more prominent French figures to lead the resistance to Adolf Hitler.
Still, the speech was an essential moment, enabling De Gaulle to claim that the French state had not surrendered but, improbable as it might appear, had moved to London. It also reflected his pragmatism; he was sure Hitler would eventually be defeated and he wanted to ensure that France came out of the war on the side of the winners as an independent nation that would not be subjected to military occupation, as Franklin D Roosevelt planned.
As I wrote my new biography of De Gaulle, published to coincide with the anniversary this week, the question keeps coming up of how this tall, gawky soldier who had been made a junior minister only a couple of weeks earlier and had now, in effect, staged a rebellion against the government of his country with a handful of followers, became the embodiment of France.
Today, 42 years after he founded the Fifth Republic, De Gaulle is – like it or not – the template against which French leaders are judged. His conception of the executive president, directly elected by the people at large, endures. His quasi-religious devotion to the strong, centralised state is evident in the difficulty that Sarkozy, like some of his predecessors, has in introducing reforms seen as threatening the authority of that state and the benefits it confers on those who work under its umbrella.
In Europe, De Gaulle's recognition of the fundamental importance of Franco-German rapprochement after three wars remains key to French policy even when, as at present, the air between Paris and Berlin is far from warm.
Further afield, his suspicion of American designs on the world, nurtured by his scratchy wartime relations with Roosevelt and then bolstered by his opposition to the war in Vietnam and his insistence on Europe asserting its independence of Washington, continues to find strong echoes in France, even if Sarkozy has overturned his decision to pull French forces out of Nato's integrated military structure. His vision of France acting as a bridge with what used to be called the "third world" is still evident in attempts by Paris to foster a Mediterranean community and the global cultural role the country sees for itself.
As for Franco-British relations, the order of the day is smiles all round as Sarkozy visits De Gaulle's wartime headquarters beside St James's Park and Resistance veterans make the Eurostar trip before returning to Paris for ceremonies there in the evening. The recurrent, sometimes violent wartime rows between De Gaulle and Winston Churchill will be shrugged off as being the way great men sometimes act under pressure. The general's subsequent dismissal of Britain as a US poodle and his 1963 veto on Harold Macmillan's bid to join the Common Market will not be mentioned – though the Eurosceptics in David Cameron's party may regard De Gaulle as a saviour in disguise.
As it has turned out, the European Union based on the primacy of the nation states which De Gaulle preached is close to the policies followed by London since Margaret Thatcher. On the French side, Sarkozy may be moving towards a relationship with Washington not too far from that Cameron will craft. So there are points of convergence, while the tough economic measures George Osborne will unveil in his budget have certain similarities with the harsh economic medicine implemented in France as De Gaulle set up the Fifth Republic.
But this should not lead one to ignore the basic reservations De Gaulle always had about the country across the narrow sea. This dated back to the Fashoda Incident, in which Britain bested France in Africa during his boyhood. In the 1930s, he denounced French politicians for following London's lead too closely in dealing with Hitler. During the war, he – rightly – concluded that once the United States had entered the conflict, London would always side with Washington. That remained his leitmotif during his decade as president of the Fifth Republic, and gave historic resonance to the opposition of the Chirac administration to the war in Iraq.
This was not so much crude Anglophobia (or Americanophobia) but the result of De Gaulle's core belief in the greatness of France, with which he associated himself in a visceral personal manner. Starting on 18 June 1940, he performed a magisterial conjuring trick in asserting France's stature (and his own) against all the odds. He did so again after returning to power in 1958. The trick wore off as he aged and as his jeremiads against US policy carried less and less weight and his outbursts such as his cry of "Vive le Québec Libre" appeared more and more as an effort by an old man to regain his former glory and influence.
Forty years after De Gaulle's death, his successors are stuck with his legacy, but exercising it in the changed world is a mammoth task. His shadow lies over France, for good or ill. That is unlikely to change for one simple reason. When he claimed that he and his country were as one, De Gaulle was not wrong. France's strengths, weaknesses and contradictions were all contained in him. The Gaullist heritage is, thus, intimately bound up with the nature of France. Neither is likely to change.
Jonathan Fenby, a British journalist.