The environment secretary has urged people to keep calm, amid warnings of "extreme danger" as a tidal surge approaches England's east coast.
Hilary Benn said eight severe flood warnings were in place, RAF helicopters were on standby and high-volume water pumps were being moved to East Anglia.
Mr Benn said gold command teams to co-ordinate emergency services had been set up in Norfolk and Suffolk.
He advised people to listen for updated information on TV and radio.
He also urged them to keep an eye on elderly neighbours.
Earlier Prime Minister Gordon Brown chaired a meeting of the emergency Cobra committee.
The Norfolk coast, East Anglia, North Kent and Dover are thought to be most at risk from the 3m surge.
Hundreds of people in Norfolk have been moved to safety, two rest centres have been set up and people living in low-lying areas of the Suffolk coast have been advised to leave their homes.
Care homes and hospitals in Great Yarmouth have been evacuated.
Low pressure and strong winds are causing the surge.
The Environment Agency predicts the highest water levels will hit Immingham, near Grimsby, at around 0430 GMT on Friday and the East Anglian coast along the Broads, Great Yarmouth and Lowestoft between 0700 and 0800.
Mr Benn said Environment Agency staff were patrolling in Norfolk and Suffolk, offering advice.
He said: "If you are advised to evacuate please follow those instructions, there are rest centres that are being set up.
"And it's really important, keep away from the sea because as well as the storm surge there will also be waves and this is dangerous and people need to keep away from it."
The Cobra meeting had included updates from the Met Office, the Environment Agency, officials in charge of getting information out to people and gold commanders in Norfolk and Suffolk by telephone, he said.
"Cobra's job is to ensure that everything that can be done is being done," he said.
"We are doing all that we can but we are just going to have to wait and see what happens as the surge makes its way down."
The latest flooding situation can be checked on the Environment Agency website or on its Floodline 0845 988 1188.
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