A dramatic search operation is underway after a fully clothed man was spotted walking into the sea.

A coastguard helicopter and lifeboats have been combing the area opposite the Concorde club near Brighton Marina since a member of public raised the alarm at around 11am.

Searchers initially saw the man in the sea but lost sight of him soon afterwards. He has not yet been found or recovered.

A Sussex Police spokeswoman said: "The reasons for his entering the sea, and his identity, are not known at this stage."