Charles de Gaulle, a junior minister in a collapsing government and a relatively junior general in an army that was ceasing to exist, landed at Heston airport after a gruelling and perilous flight from Bordeaux, on Monday 17 June 1940. Few of his British hosts knew who he was, Winston Churchill being the exception. During his visits to France, Churchill had immediately noticed “a young, energetic general called de Gaulle.” `(In Gabriel Le Bomin’s biopic of de Gaulle, which features the early days of the two men’s relationship, Churchill is brilliantly played by Tim Hudson – who is also a London Blue Badge Guide!)

London covers 600 square miles and has a population of 8.6 million, but only its oldest part, just one square mile in size, is called the City of London. That is where the Romans founded the city of Londinium shortly after they arrived in 43AD. Today, the City of London – or simply “the City” – is the centre of London’s finance industry. The City is where you find the Bank of England, the London Stock Exchange, the investment banks, insurance companies and financial markets. It combines the most modern headquarters buildings with Roman remains and medieval churches, and it is great to explore on foot.