The Thames Barrier is officially opened, preventing the floodplain of most of Greater London from being flooded except under extreme circumstances.

The Thames Barrier is a retractable barrier system built to protect the floodplain of most of Greater London from exceptionally high tides and storm surges moving up from the North Sea. It has been operational since 1982. When needed, it is closed (raised) during high tide; at low tide, it can be opened to restore the river's flow towards the sea. Built about 2 miles east of the Isle of Dogs, its northern bank is in Silvertown in the London Borough of Newham and its southern bank is in the New Charlton area of the Royal Borough of Greenwich.

A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high discharge. The soils usually consist of clays, silts, sands, and gravels deposited during floods.

Greater London is an administrative area in England, coterminous with the London region, containing most of the continuous urban area of London. It contains 33 local government districts: the 32 London boroughs, which form a ceremonial county also called Greater London, and the City of London. The Greater London Authority is responsible for strategic local government across the region, and regular local government is the responsibility of the borough councils and the City of London Corporation. Greater London is bordered by the ceremonial counties of Hertfordshire to the north, Essex to the north-east, Kent to the south-east, Surrey to the south, and Berkshire and Buckinghamshire to the west.

May 8 is the 128th day of the year in the Gregorian calendar; 237 days remain until the end of the year.