TQ4681 : Thames Barrier control zone warning, Creekmouth

On the left is the Barking Creek barrier. In the right is a warning device placed ahead of the beginning of the Thames Barrier control zone which starts just above the mouth of Barking Creek. There is another board level with this one on the other side of the Thames which gives a written warning, but this one is believed to be a huge loudspeaker for use in poor visibility.