Hundreds of paramedics, firefighters and police are taking part in a simulation in the port of Dover.
Crews will be cleaning up a simulated chemical spill from a lorry which has accidentally dropped its hazardous cargo.
Officers are keen to stress that this is an exercise so residents should not be alarmed if they hear sirens in the area.
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A group of divers have commemorated one century since the end of World War One by hanging a plaque on the bow of a shipwreck off Shoreham.