The warning comes from the RNLI after a spate of rescues at the mouth of the River Arun in Littlehampton, where powerful tides have swept several people into danger. Nick White, lifeboat operations manager at Littlehampton RNLI, said: "Along with our lifeguards, we have been called out to a number of incidents in the River Arun and harbour. The latest rescue took place on June 26, when RNLI lifeguards launched their inshore rescue boat to help two teenagers who had been swept into the river mouth from West Beach. They are also advising against entering the water on the west side of the river, where there are no lifeguards. "If you find yourself in difficulty in the water, remember Float To Live: Tilt your head back, submerging your ears.