In a chilling development one year into the Second World War, Germany began a bombing campaign on British cities on this day in 1940 that would see more than 40,000 civilians killed in a period of just over eight months.

Known as the Blitz (shortened from the German word blitzkrieg, meaning ‘lightning war’), the bombing campaign was an attempt by the Luftwaffe to wage economic warfare against Britain by striking its industries, communications and supply bases.

Adolf Hitler was also convinced of the efficacy of bombing as a weapon of terror – striking fear into the hearts of civilians who would then put pressure on the government to capitulate. Additionally, the failure of his air force to gain superiority over the RAF during the Battle of Britain called for a major shift in policy, having delayed Operation Sealion, his plan to invade the country.

[Read more: November 14, 1940 - Coventry Cathedral is destroyed by German bombs]

As recalled in the video above, the first wave of attacks on London came from 348 German bombers, escorted by 617 fighters, between around 4pm and 6pm on Saturday September 7. Two and a half hours later, using fires started by the first wave to guide them, more bombers pounded the city in an assault that continued until 4.30am.

British air defences, which were largely geared to daytime attacks, were vastly unprepared for the ferocity of the assault – though the night time campaign would also prove costly for the Luftwaffe, with the Air Ministry claiming 88 German planes shot down against 22 from the RAF.

[Read more: December 29, 1940 - St Paul's stands defiant as second Great Fire of London rages]

By the end of the day, 337 tons of bombs had been dropped on the capital, with the East End and South East of the city being worst affected. Even though civilian populations were not the primary target that day, more than 400 people were killed that afternoon and evening, and hundreds more were injured.

London would be bombed for a total of 57 consecutive nights, while 15 other industrial and port cities would be heavily targeted – but against all odds civilian morale remained high, while industrial production was never seriously hampered.