French President Nicolas Sarkozy is visiting London to mark the 70th anniversary of General Charles de Gaulle's appeal to his countrymen to resist the Nazi occupation of France. General de Gaulle's broadcast from a BBC studio on June 18 1940 - the day after Marshal Philippe Petain's government announced its surrender to the Germans - is widely seen as the founding act of the Second World War French resistance. Few Frenchmen actually heard Gen de Gaulle declare over the airwaves that "the flame of French resistance must not and will not be extinguished". But further broadcasts in the following days led to him becoming so well-known that he was subsequently court martialled in his absence and sentenced to death for treason. The British Government had originally not wanted to allow him to issue his rallying cry, but the Cabinet was persuaded by Prime Minister Winston Churchill to let him go ahead. The visit by Mr Sarkozy - the first French president to mark the anniversary in London.