“We will not lose hope,” the wife of missing TV and radio presenter Michael Mosley has said, as the search continues on the Greek island of Symi.

The 67-year-old vanished after leaving a beach to set off on a walk on Wednesday.

His wife Dr Clare Bailey Mosley said in a statement that the days since he went missing had been “the longest and most unbearable”.

On Saturday, a search and rescue operation resumed for Dr Mosley, known for his TV programmes and BBC Radio 4’s Just One Thing podcast.

In her statement, Dr Bailey Mosley said: “It has been three days since Michael left the beach to go for a walk. The longest and most unbearable days for myself and my children.

“The search is ongoing and our family are so incredibly grateful to the people of Symi, the Greek authorities and the British Consulate who are working tirelessly to help find Michael.

“We will not lose hope.”

Dr Bailey Moseley has been searching the island assisted by friends. The couple’s four children have also arrived on Symi to help with the search.

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 mountainous terrain was described as “not easy” by those involved with the search.

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

Earlier on Saturday, firefighters started searching a 4 mile (6.5km) radius over a mountainous area that is surrounded by sea.

Asked if there had been any sign of Dr Mosley, he said there has been “nothing”.

One theory that has emerged was 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.