Flooding in Britain has spread along the River Thames and begun to threaten London, as a political row over the handling of devastating winter storms erupted.
The Environment Agency issued 14 severe flood warnings - meaning lives are at risk - in the affluent counties of Surrey and Berkshire to the west of the capital, after the Thames broke its banks.
Some areas are already under water, including parts of the Great Windsor Park, the grounds of the Queen's castle at Windsor, which itself is built on higher ground.
The Berkshire fire service rescued at least 16 people on Monday, including several from their homes in the flooded village of Wraysbury, a spokeswoman said.
In the village, residents donned waders and even a full wetsuit as the waters rose. Some complained that the village had been abandoned by the authorities, who are already under fire over their handling of flooding in southwest England.
Somerset in southwest England has been under water for weeks after the wettest January since 1766, and more bad weather is expected over the coming days.
Devastated communities have criticised the official response, saying more should have been done to protect their properties from flooding.
The government last week announced STG130 million ($A239.41 million) in extra funding for emergency repairs and maintenance.
On a visit to Dorset in southwest England, Cameron called for calm as he viewed how the military are helping build up sea defences against weeks of punishing waves.
London itself is protected by the Thames Barrier, although a suburb to the south of the capital, Croydon, announced plans to divert rising floodwaters caused by heavy rain away from homes and businesses by pumping them into a pedestrian underpass.
