UPDATED:Major search launched after cross channel swimmer disappears attempting to reach Calais

A search is underway to find a swimmer who set off alone from Dover earlier today, without any accompanying safety vessel, in an attempt to reach Calais. A coastguard rescue helicopter and Dover lifeboat are heading up the search. Vessels in the Channel have been asked to keep a lookout. UPDATE: A swimmer who prompted an air-sea search operation in the English Channel after swimming unaccompanied from Calais was spotted by a passing vessel 500m from Dover and brought to shore, the Coastguard said.