Officers have only released his first name, Ben.

He was last seen in the city on Monday, 6 October.

He has light brown hair and was last seen wearing a black puffa jacket, walking boots and carrying a large backpack.

Ben has links to Bexhill, Eastbourne and Hastings but he has previously travelled around the UK and been found in wooded areas, and he also has links to Bristol, Scarborough, Edinburgh, London, Scotland, Leicester and North Yorkshire.

Anyone who sees him or knows of his whereabouts should call 101 quoting serial 952 of 05/11.