Over 1,000 homes in Plymouth, Devon, were ordered to evacuate on Sunday, May 10, 2026, after construction workers unearthed a 500-kilogram German SC250 air-drop bomb — one of the largest unexploded WWII devices ever found in the United Kingdom — prompting a large-scale military response and a controlled detonation that shattered windows across the city.
Emergency services were called to Devonport, a district in the city of Plymouth on the southern coast of England, at approximately 07:40 BST on Sunday morning after construction workers grading a site for new housing development struck the bomb at a depth of roughly 2.5 metres below the surface. Devon and Cornwall Police immediately established a 500-metre exclusion zone, and Plymouth City Council worked with the Royal Navy and British Army’s unexploded ordnance disposal (UXO) teams to coordinate the evacuation of an estimated 1,000 to 1,200 residential properties across three postcode sectors.
Police Inspector Kevin Hoskins, speaking at the scene, confirmed that the device was identified as a 500-kilogram SC250 — a semi-armour-piercing air-drop bomb manufactured in Nazi Germany during the Second World War, fitted with a delayed-action fuse designed to detonate on impact or shortly after landing. “This is an exceptionally large device by any standard,” Hoskins said. “Our primary concern was the civilian population. We needed to get people clear before we attempted any handling.”
The bomb was moved — under military escort and with a police outriders detail — to a pre-selected detonation site at a disused quarry approximately 3.2 kilometres northeast of the discovery location. British Army specialist explosive ordnance disposal (EOD) teams from 33 Engineer Regiment conducted the operation, supported by Royal Navy diving teams familiar with maritime explosive handling.
The controlled detonation was carried out at 14:22 BST on Sunday afternoon. The explosion was heard across the Plymouth urban area and registered on local seismographs. Devon and Cornwall Police received more than 340 calls within 20 minutes of the blast, the vast majority from residents reporting a loud noise and window vibrations. No injuries were reported. Structural damage to nearby properties — including several 1930s-era terrace houses — was confirmed at 17 properties, ranging from cracked plaster to a small number of broken windowpanes.
“The detonation went as planned. Our team executed the disposal exactly as rehearsed. The device is no longer a threat to the public.” — British Army EOD Team Spokesperson, 33 Engineer Regiment
Plymouth is not unique in harbouring unexploded WWII ordnance. The city was subjected to some of the heaviest bombing raids of any British urban centre during the Blitz, with a particular concentration of attacks targeting the naval dockyard at Devonport — now HMNB Devonport, one of the United Kingdom’s three naval bases — and the associated industrial zones in the city centre. Historical records from the Plymouth City Council and Imperial War Museum estimate that the Luftwaffe dropped approximately 2,900 tonnes of high-explosive bombs on Plymouth between September 1940 and April 1944.
Estimates from the British Geological Survey and Ministry of Defence suggest that between 10 and 15 percent of WWII-era air-drop bombs in the United Kingdom failed to detonate on impact — meaning that for every ten tonnes of bombs dropped, between one and 1.5 tonnes may still lie in the ground across the country. A 2023 survey commissioned by the Chartered Institute of Civil Engineering estimated that Plymouth alone contains an unexploded bomb density of approximately 1 device per 2.7 square kilometres of previously developed land, among the highest in the United Kingdom.
Similar large-scale evacuations have occurred in recent years. In 2021, a bomb disposal operation in Exeter required the evacuation of over 7,000 people. In 2019, Grimsby saw a 900kg bomb handled and destroyed. London, which received the largest volume of aerial bombardment of any British city, still regularly discovers devices during construction works, with a 500kg bomb found in Poplar in 2017 requiring a 2.5km exclusion zone.
Plymouth City Council opened emergency rest centres at three community centres and two schools within the exclusion zone, providing more than 600 people with hot meals, drinks, and temporary accommodation. Local hotel groups offered reduced-rate rooms, and the Plymouth & District Community Union assisted with the transport of residents with mobility requirements.
“Plymouth has lived with the legacy of war in its ground for 80 years. This was a serious moment, and our emergency services responded with extraordinary professionalism. The city is safe tonight, and the device is gone.” — Plymouth City Council spokesperson
Councillors announced on Monday morning that a formal review of construction safety protocols for deep excavation works in Plymouth will be brought before the full council at its next session, with potential implications for pre-construction bomb surveys required before any development on sites in the Devonport and Stonehouse districts.
