The 'Blitz on Coventry' was a series of German bombing raids against the the British city of Coventry (1940/42).

At the start of World War II in 1939, Coventry was an industrial city of around 238,000 people and, like much of the industrial West Midlands, contained metal- and wood-working industries. In Coventry’s case, these industries the manufacture of cars, bicycles, aeroplane engines and, since 1900, munitions.

During World War I, the advanced nature of the mechanical tooling industry in the city meant that pre-war production of civilian goods could quickly be turned to war production purposes, with industries such as the Coventry Ordnance Works becoming one of the leading munition centres in the UK, manufacturing 25% of all British aircraft produced during the war.

Like many of the industrial towns of the West Midlands region that had been industrialised during the industrial revolution, many of the small- and medium-sized factories in the city were woven into the same streets as their workers' houses and the shops of the city centre. However, between World War I and World War II, however, Coventry had seen the development of many large suburbs of both private and council housing, which were relatively isolated from industrial buildings. The city was also at the centre of the UK’s car industry, with many carmakers based at different locations in Coventry, and many of these factories had switched to boost the supply of items for the war effort.

There were 17 small raids on Coventry in the 'Battle of Britain' period between August and October 1940, and in these about 198 tons of bombs were dropped. Together, the raids killed 176 people and injured around 680.  The most notable damage was to the new Rex Cinema which had been opened in February 1937 and had already been closed by an earlier bombing raid in September.

On 17 October 1940, 2^nd Lieutenant Sandy Campbell of the Royal Engineers Bomb Disposal Company was summoned to deal with an unexploded bomb that had fallen at the Triumph Engineering Company’s works in Canley. War production in two factories had ceased on a temporary basis because of it, and many nearby residents had been evacuated. Campbell found that the bomb was fitted with a delayed-action fuse that was impossible to remove, so he transported the bomb to a safe area using a truck, Campbell lay alongside the bomb so that he could hear if it started ticking and could warn the driver to stop and run for cover. Having taken it a safe distance, he disposed of the bomb successfully but was killed while dealing with another bomb on the following day.

The raid which started during the evening of 14 November 1940 was the most severe to hit Coventry during the war. It was carried out by 515 bombers of Generalfeldmarschall Hugo Sperrle’s Luftflotte III and the pathfinders of Hauptmann Kurt Aschenbrenner’s Kampfgruppe 100. This 'Mondscheinsonate' was intended to destroy Coventry’s factories and industrial infrastructure, although it was clear that damage to the rest of the city, including monuments and residential areas, would be considerable. The initial wave of 13 specially modified Heinkel He 111 twin-engined aircraft of the Kampfgruppe 100, which were equipped with X-Gerät navigational devices, accurately dropped marker flares at 19.20. The British and the Germans were fighting the 'Battle of the Beams', and on this night the British failed to disrupt the X-Gerät signals.

The first wave of follow-up bombers dropped high explosive bombs, knocking out the utilities (the water supply, electricity network, telephones and gas mains) and cratering the roads, making it difficult for the fire engines to reach fires started by the later waves of bombers. These later waves dropped a combination of high explosive and incendiary bombs. There were two types of incendiary bomb: magnesium and petroleum. The high explosive bombs and the larger air mines not only hindered the efforts of Coventry’s fire brigade, but were also intended to damage roofs, making it easier for incendiary bombs to fall into buildings and set them on fire.

Coventry’s defences against air attack comprised 24 3.7-in (94-mm) and 12 40-mm Bofors anti-aircraft guns. The AA Defence Commander of 95^th (Birmingham) Heavy Anti-Aircraft Regiment, Royal Artillery, had prepared a series of concentrations to be fired using sound locaters and GL Mk I gunlaying radar, and 128 concentrations were fired before the bombing severed all lines of communication and the noise drowned out sound location. The anti-aircraft batteries then fought on in isolation. Some gun positions were able to fire at searchlight beam intersections, glimpsed through the smoke and guessing the range and altitude. Although the Coventry guns fired 10 rounds a minute for the whole 10-hour raid, only one German bomber was shot down.

At about 20.00, Coventry Cathedral was set on fire by incendiaries for the first time. The volunteer firefighters managed to put out the first fire but other direct hits followed and soon new fires broke out and, accelerated by a firestorm, the flames quickly spread out of control. During the same period, more than 200 other fires were started across the city, most of which were concentrated in the city’s centre, setting the area ablaze and overwhelming the firefighters. The telephone network was crippled, hampering the fire service’s command and control and making it difficult to send firefighters to the most dangerous blazes first; as the Germans had intended, the water mains were damaged by high explosives, meaning there was not enough water available to tackle many of the fires. The raid reached its climax around 00.00, and the all-clear was sounded at 06.15 on the morning of 15 November.

In one night, more than 4,300 homes in Coventry had been destroyed and around two-thirds of the city’s buildings damaged. The raid had been heavily concentrated on the city centre, most of which had been destroyed. Two hospitals, two churches and a police station had also been damaged. The local police force lost no fewer than nine constables or messengers in attack. About one-third of the city’s factories had been completely destroyed or severely damaged, another one-third had been badly damaged, and the rest had suffered slight damage. Among the destroyed factories were the main Daimler factory, the Humber Hillman factory, the Alfred Herbert Ltd machine tool works, nine aircraft factories, and two naval ordnance stores. However, the effects on war production were only temporary, as much essential war production had already been moved to 'shadow factories' on the city outskirts. Also, many of the damaged factories were quickly repaired and had recovered to full production within a few months.

An estimated 568 people had been killed in the raid, although the exact figure was never precisely confirmed, with another 863 badly injured and 393 suffering lesser injuries. Given the intensity of the raid, the number of casualties were limited by the fact that a large number of Coventry’s population had 'trekked' out of the city at night to sleep in nearby towns or villages following the earlier air raids. Also, people who took to air raid shelters suffered very little death or injury. Out of 79 public air raid shelters holding 33,000 people, very few had been destroyed.

Although the city centre suffered the heaviest raids, districts of the city including Stoke Heath, Foleshill and Wyken were also heavily bombed.

During the raid, the Germans dropped about 500 tons of high explosive bombs, including 50 parachute air mines, of which 20 were incendiary petroleum mines, and 36,000 incendiary bombs.

The 'Mondscheinsonate' raid of 14 November combined several innovations which influenced all future strategic bomber raids during the war.  These were firstly the use of pathfinder aircraft with electronic aids to navigate, to mark the targets before the main attack, and secondly the use of high explosive bombs and air mines (blockbuster bombs) coupled with thousands of incendiary bombs intended to set the city ablaze in a firestorm.

In Allied raids later in the war, 500 or more four-engined heavy bombers all delivered their typical 3,000- to 6,000-lb (1361- to 2722-kg) bomb loads in a concentrated wave lasting only a few minutes. At Coventry, however, the German twin-engined bombers carried smaller bomb loads, in the order of 2,000 to 4,000 lb (910 to 1815 kg), and attacked in smaller multiple waves. Each bomber flew several sorties over the target, returning to base in France to rearm between sorties. Thus the attack was spread over several hours, and there were lulls in the raid when firefighters and rescuers could reorganise and evacuate civilians.

The British exploited the opportunity given them by the attack on Coventry to try a new tactic against Germany, which was carried out on 16 December 1940 as part of 'Abigail Rachel' against Mannheim. The British had been awaiting the opportunity to experiment with an incendiary-intensive raid, considering it a kind of retaliation for 'Mondscheinsonate'. This marked the start of thea British drift away from precision attacks on military targets in favour of area bombing attacks on whole cities.

In a 1974 book, Group Captain F. W. Winterbotham asserted that the British government had advance warning of the attack from 'Ultra' intelligence, which used intercepted German radio messages encrypted with the Enigma cipher machine and decoded by British cryptanalysts at Bletchley Park. He further claimed that Prime Minister Winston Churchill ordered that no defensive measures should be taken to protect Coventry, lest the Germans suspect that their cipher had been broken. Winterbotham’s claim has been rejected by other 'Ultra' participants and by historians, however, who state that while Churchill was indeed aware that a major bombing raid would take place, no one knew what the target would be.

The scientist Dr R. V. Jones, who led the British side in the 'Battle of the Beams', wrote that 'Enigma signals to the X-beam stations were not broken in time' and that he was unaware that Coventry was the intended target. Furthermore, British were yet unaware that Luftwaffe moved from their pilots manually listening of the signals to an automatic narrow-band onboard receiver, and that caused jamming countermeasures to be ineffective. Jones also noted that Churchill returned to London that afternoon, which indicated that Churchill believed that London was the likely target for the raid.

On the night of 8/9 April Coventry was subject to another large raid in which 230 bombers attacked the city, dropping 315 tons of high explosive and 25,000 incendiaries. In this and another raid two nights later, on 10/11 April, about 451 people were killed and more than 700 seriously injured.  Damage was caused to many buildings including some factories, the central police station, the Coventry & Warwickshire Hospital, King Henry VIII School, and St Mary’s Hall. The main architectural casualty of the raid was Christ Church, most of which was destroyed, leaving only the spire.

The final air raid on Coventry came on 3 August 1942, in the Stoke Heath district about 1 mile (1.6 km) to the east of the city centre. Six people were killed. By the time of this air raid, some 1,236 people had been killed by air raids on Coventry; of these, 808 rest in the mass grave in London Road Cemetery: some 80% of them had been killed in the raids of 14/15 November 1940 and 8/10 April 1941.

Immediate reconstruction was undertaken by a committee headed by the motor industry magnate William Rootes. In the aftermath of the war, Coventry city centre was extensively rebuilt. Coventry Cathedral was left as a ruin, and is today still the principal reminder of the bombing. Spon Street was one of the few areas of the city centre to survive the Blitz largely intact, and during the post-war redevelopment of Coventry, several surviving mediaeval buildings from across the city were relocated to Spon Street. The 14^th century St Mary’s Guildhall in Bayley Lane opposite the ruined cathedral also survived and stands to this day. However, in addition to destroying many historic buildings, the bombing revealed a mediaeval stone building on Much Park Street, thought to date from the 13^th or 14^th century.