- Theatre: United Kingdom
- Dates:25 August 1940 to 16 May 1941
- Location: London and other major cities
- Outcome: Allied victory at a high civilian cost. The Blitz reduced pressure on the RAF, cost Germany enormous numbers of aircraft and personnel and failed to pave the way for the German invasion of Britain.
- Britain: RAF Fighter Command under Air Chief Marshal Sir Hugh Dowding
- Germany: Luftflotten 2 under Field Marshal Albert Kesselring, based in north east France; Luftflotten 3 under Field Marshal Hugo Sperrle, based in the Low Countries
The sustained German bombing of London and other major British cities began towards the end of the Battle of Britain, after a British raid on Berlin in early September prompted Hitler to order the Luftwaffe to switch its attention from RAF Fighter Command to urban centres of industrial and political significance.
The first German raids on British cities had already taken place by the end of August 1940, when Birmingham and Liverpool were attacked, but on 7 September the Blitz intensified when around 950 German aircraft attacked London. It was the first and last mass daylight raid on London, but it heralded the first of 57 consecutive nights of bombing.
The daylight raid alone caused some 300 civilian deaths and a further 1,300 serious injuries; by the end of the Blitz, around 30,000 Londoners would be left dead, with another 50,000 injured. Fortunately, millions of children, mothers, patients and pensioners had already been evacuated to the countryside.
For those who were left in London, a rigorous policy of blackout began. Every building had to extinguish or cover its lights at night, and car owners had to reduce their headlights to a thin horizontal slit, with rear lamps also dimmed severely. Road accidents shot up, exacerbated by the lack of street lighting and the dimmed traffic lights.
A second daylight raid on 9 September was successfully intercepted by Fighter Command's 10, 11 and 12 Groups. Less than half of the German bombers got through, with very few hitting their targets.
Daylight attacks continued elsewhere in England, with sporadic success. Against London, however, the Germans haemorrhaged aircraft and crew, compared to much lighter British losses.
In early November, Luftwaffe chief Reichsmarschall Herman Göring ordered that the air offensive against cities, industry and ports had to be conducted entirely under cover of darkness. The new strategy was showcased by a massive attack on Coventry on 14 November, which destroyed much of the city, including all but the spires of St Michael's Cathedral and the Grey Friars' Church. Attacks on Birmingham, Southampton, Bristol, Plymouth and Liverpool followed, but they proved less effective.
On 29 December, a major raid on London destroyed much of the City, but poor winter weather then led to a drop in attacks until March. The two months from March until May 1941 saw a series of heavy attacks, culminating in a very damaging raid on London on 10 May. The Blitz ended on 16 May, when most of the Luftwaffe was re-assigned east for the imminent invasion of Russia.
The end of the Blitz saw a return of evacuees and the start of the reconstruction of London - even though building materials were in desperately short supply. The docks had been devastated, as had many industrial, residential and commercial districts, including the historic heart of the City.