A Sussex man is feared dead after he was spotted plunging from a cross-Channel ferry.

The skipper of the Brittany ferry, Bretagne, raised the alarm when the passenger was seen plunging overboard three miles south east of the Isle of Wight.

An air and sea search was launched, but no trace was found of the man and the search was abandoned.

A roll call of crew and 1,716 passengers on board the ferry was carried out half an hour into the overnight crossing from Portsmouth to St Malo on Saturday night.

Through a process of elimination, the man believed to have jumped was identified.

The ship's crew found a bag on the deck and an unclaimed car on the car deck, which have been traced to a man from Bognor.

Solent Coastguard watch manager Annette McHugh said: "Items in the bag relate to the owner of the car but, having conducted an extremely thorough search of the area, no sighting of the missing man has been made."

The coastguard helicopter and lifeboats were joined in the search by a fisheries research vessel and three other privately-owned boats which were in the area at the time.

The helicopter was called off shortly after midnight and the boat crews gave up the search more than two hours later.

Toby Oliver, a spokesman for Brittany Ferries, said: "A passenger reported seeing someone jumping into the water an hour-and-a-half into the nine-hour crossing.

"The ship was stopped and a fast rescue boat lowered into the water to try to find the man but it was unsuccessful."

A spokesman for Hampshire Police said: "Police officers have spoken to the man's family in Bognor Regis and Bournemouth and his father has now reported him as a missing person."

He added that if the man had jumped overboard it could be months before a body was washed on to the beach in France or England.

Possible witnesses were due to be interviewed by police on their return to Portsmouth. Police are refusing to identify the man until all relatives have been informed.