(Bloomberg) -- The unexploded Nazi bomb that closed London City Airport for more than 24 hours this week after being found during construction work was detonated by the Royal Navy after being towed out to sea.
The device, which weighed 500 kilograms (1,100 pounds) and measured 1.5 meters (5 feet) long, was destroyed in a controlled explosion in the Thames estuary shortly after midday Tuesday, a Ministry of Defence spokeswoman said.
London City, a key hub for travel to the U.K. capital’s financial district, was forced to close Sunday after the ordnance was found in the adjoining George V dock. Police evacuated the area while divers worked to remove the bomb, described by the MoD as the biggest type most commonly dropped by the Luftwaffe.
While the device -- known as a tapered-end shell -- was successfully removed from 15 meters of water and floated down the Thames to a point off the Essex coast for detonation, a 30-knot wind and 2-meter sea swell meant conditions weren’t initially suitable for it to be blown up, according to the MoD.
More than 20,000 tons of explosives fell on London during the German Blitz, killing 40,000 people. At least 20 percent of the bombs dropped in a total of 85 raids are thought not to have detonated.
More unexploded devices have been discovered in recent years as intensive building works on projects such as Crossrail disturb ground untouched since the conflict ended 75 years ago. About 450 German bombs have been found since 2010, or about 60 a year.
London’s East End was a major target for Luftwaffe bombers seeking to put the dock network out of action. London City airport itself is built between former harbor basins.
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