3 September 1939: Britain declares war
The end of appeasement: Britain and France declare war on Germany
The German invasion of Poland represented a shocking personal rebuff for Neville Chamberlain. On Sunday 3 September he announced, in one of the most famous broadcasts in British history, that no response had been received to his ultimatum and that, in consequence, Britain and Germany were at war.
This photograph, looking towards Admiralty Arch across the southern end of Trafalgar Square, catches the slightly bemused mood of an almost deserted London on a hot bank holiday weekend.
This excerpt is taken from a broader feature by military historian Richard Holmes, The Road to War in Pictures, published in the September issue of BBC History magazine