Sea defences in Great Yarmouth and
The Norfolk Broads, Essex and northern Kent could also be hit, and the entire coast from Immingham in Humberside to
The Environment Agency, which issued eight severe flood warnings, last night said it was "gravely concerned" about the threat.
The tidal surge is being caused by 50mph winds in the North Sea, an unusually high tide and an area of low pressure off the East Coast.
Simon Hughes, of the Environment Agency, said: "Great
It is expected to measure almost 5ft above what is normally expected - but in the worst case, it could be more than 9ft higher.
Mr Hughes said the defences were almost 10ft high, "so it's going to be close and we are gravely concerned. The most important thing that people can do is contact the Environment Agency's Floodline to see if they will be affected. If they are, they can move valuables upstairs, move their vehicles and ensure that their neighbours are safe."
The surge has echoes of the East Coast floods of 1953, when more than 1,000 people died.
"Things are very different now," said Mr Hughes. "We have flood defences, a warning system and the emergency services are well prepared and practice for floods."
Around 8,000 homes in Great Yarmouth could be at risk, along with 1,800 in