Piers Hopson, of Southwater Road, St Leonards, disappeared last Monday (January 25).

Police said he left his home at around 2.30pm saying he was going for a walk but did not return home.

Officers said this week they have a confirmed sighting of the 35-year-old, who suffers from Asperger's Syndrome, at Ore railway station last Monday, where he was spotted reading a newspaper on the platform shortly after 4pm.

He had caught a train from St Leonards Warrior Square.

His mum Dawn, who lives in Crowborough, said: "It's dreadful and we don't know what to do. Police are looking for him everywhere.

"He disappeared before at the beginning of December while out walking from Battle to Heathfield. He did not have his mobile phone with him and had to spend the night in a bus shelter."

Mrs Hopson said her son had mistakingly missed the last bus and was found the following day waiting for the next one at the shelter.

She said: "Piers enjoys walking everywhere. In recent weeks he has walked around Rye and Winchelsea with staff from his care home."

His mum said her son had £45 on him last Monday and was wearing a mushroom-coloured anorak, dark trousers and brown shoes.

The search for Mr Hopson has been extended into neighbouring Kent.

Sussex Police are working with British Transport Police and Kent Police in the hunt.

A spokesman for Sussex Police said there had been possible sightings of him in Tunbridge Wells.

She said: "There was a TV appeal on Wednesday evening which resulted in people calling in to report possible sightings, one of them being in the Hastings area.

"We are looking at CCTV footage from both Ore and St Leonards Warrior Square stations, as well as Tunbridge Wells station."

Police visited the last known whereabouts of Mr Hopson on Monday, exactly a week after his disappearance.

Officers handed out posters and spoke to passengers and staff.
Leaflets with Mr Hopson's photograph have also been distributed across the South East and London.

Police are also investigating possible sightings of him in the Hailsham area.

Mr Hopson's condition, a form of autism, means he struggles to communicate with members of the public and may not necessarily ask for help.

Detective Inspector Rob Morland said: "Although there is nothing to suggest that Mr Hopson has come to any harm, we are very concerned for his well-being as he has been missing from home for over a week.

"We urge anyone who thinks they may have seen him over the past seven days to come forward.

"If you find Mr Hopson and he is unwell, please call 999 immediately to request police and ambulance attendance. If he is safe and well, please contact Sussex Police on 0845 60 70 999."