A yellow weather warning is in force for Suffolk and Essex, with the downpours leaving driving conditions hazardous.
Suffolk police are advising motorists to travel safely as they've had reports of standing water even on main carriageways.
A police spokesman said: "The conditions on the roads this morning are very difficult and it's pretty bad out there."
The rain is expected to ease off around 10am but for now drivers have been advised to drop their speed.
Trains and public transport has not yet been affected.
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