Michael Mosley's wife Clare says she won't lose hope over missing ...

Michael Mosley went missing on Wednesday after leaving his wife on Agios Nikolaos beach around 13:30 local time (11:30 BST).

His wife later reported Dr Mosley, who did not have his phone, missing.

BBC News has seen new CCTV - one of the last-known sightings - of a man believed to be Dr Mosley walking with an umbrella next to the marina in the village of Pedi on Wednesday, heading towards rocky hills.

The new footage appears to show the man in good form and walking steadily, an unnamed police officer told BBC News.

Greek authorities have since shifted their search operation to this part of the island.

In the mountainous terrain it would be easy to fall and injure yourself, or wander off the trail and get lost.

One theory that has emerged is that Dr Mosley was trying to take a much longer route than previously thought, passing over miles of exposed hillside. Dr Mosley's accommodation was in the main town about 1 mile from Pedi.

When BBC News walked a short bit of the same path Dr Mosley is believed to have followed, under the midday sun, the effects of the heat could be felt quickly.