Everything we all know up to now concerning the seek for Dr Michael Mosle

Just what has happened to Mail columnist and TV personality Dr Michael Mosley?

The 67-year-old health guru has not been seen since Wednesday after spending the morning on an idyllic beach with his wife Dr Clare Bailey, 62, who has declared ‘we will not lose hope’ as the search for the missing Mail columnist enters its fourth day.

Known for his popular 5:2 diet and for his appearances on the One Show and This Morning, the search for him has been described as a ‘race against time’.

Search teams with dogs and drones have been fanning out across the Greek island of Symi, an unspoilt paradise in the Dodecanese islands off the coast of Rhodes.

But so far, no trace of father-of-four Dr Mosley has been found, and with temperatures topping 35C under a fierce sun, there are now growing concerns for his safety.

Dr Michael Mosley’s wife vowed earlier on Saturday ‘we will not lose hope’ as her family arrived on the island of Symi to join her in the fourth day of desperate searches for the missing Mail columnist.

‘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,’ she told MailOnline in an emotional statement.

‘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.’

MailOnline can reveal that Dr Mosley and his wife arrived in Symi a week ago and were staying with friends who own a home close to the island’s main port.

Known as The Merchant’s House, it is a beautiful pastel-coloured three-bedroom property at the edge of town, owned by an architect and his lawyer partner.

The house is popular with painters, and a review says: ‘Merchant House is a beautifully restored private home situated on the hillside above the main town.

‘With its terraced garden and sea views over the rooftops, the Merchant House provides a peaceful retreat for visiting artists.’

They are close friends of Dr Mosley and his wife and are known to holiday together regularly in Symi.

On Wednesday, all four took a water taxi from Symi to St Nicholas, where they spent the morning sunbathing on the secluded pebble beach.

Around 1.30 pm Dr Mosley packed his rucksack after a swim and told his wife and friends he was going to walk back to Symi.

The route is around five miles and not particularly difficult – and CCTV picks him up as he enters the fishing village of Pedi, around 15 minutes later.

He is seen walking in a blue polo shirt, baseball cap and shorts, and carrying a distinctive purple parasol to protect himself from the heat.

Police have been able to follow his route as he walked past the Kamares café, past the Katsaras restaurant and on towards the Blue Corner café.

The last time he was seen was as he passed a private house belonging to a local man, heading along a trail that ends in Agia Marina, around 2 miles away.

But this is where the trail goes cold and, since Friday when his route was confirmed, search teams have been combing the rocky peninsula for him.

There are fears he may have become disoriented in the heat and wandered off the trail, although this seems unlikely as it is clearly marked.

On Saturday, a rescue team with a drone was joined by around a dozen British people who are thought to be friends of Dr Mosley’s children.

They fanned out along the route from Pedi to Agia Marina, accompanied by Greek search teams, but when approached refused to discuss who exactly they were.

‘Please don’t talk to us,’ said one woman, as the group headed away towards a shepherd hut on the path towards the picturesque bay at Agia Marina.

There is a path from Agia Marina which leads down into Symi but it is not marked and guidebooks warn that it is ‘technically difficult’ and easy to stumble and get lost along.

It adds the unforgiving limestone terrain is a ‘desert mountains scape with much of the path ‘stony to very stony underfoot’.

MailOnline walked a section of it and although doable it would certainly be hard work under a fierce sun during the hottest part of the day.

One search member encountered by the MailOnline said:’ We have footage of him going this way from the last house in Pedi but you can’t see the umbrella he was carrying.

‘This is a difficult walk at the best of time and should not be done between 11am and 5pm and we think he was here during the hottest part of the day at 2pm.’

At Agia Marina – a purpose-built beach with stunning views onto a small island and the Turkish coast on the horizon – staff told MailOnline police had asked them to check their CCTV.

An employee said: ‘I’m pretty certain I would have remembered a man with an umbrella but no one came this way dressed like that.

‘The owner is out with the police now searching from here to Symi. It’s a climb to the top of the mountain, then you walk down, and it climbs again before you meet a road taking you into the town. It would take about an hour, an hour and a half at most.

‘There is nothing between here and Symi apart from stones, more stones and sheep and goats, it’s all exposed and I wouldn’t try and walk it in this heat.’

Apart from goats and sheep on the peninsula, there is nothing else apart from a few isolated shepherd huts.

Symi’s mayor Eleftherios Papakalodoukas said: ‘We know he came through Pedi and then walked onwards towards Agia Marina, it is about two miles and a harder walk than from St Nicholas.

‘But then we don’t know if he reached Agia Marina or if he decided to climb over the mountain which at it’s highest is about 250m (815ft) to head into Symi but that path is difficult.

‘Only a few locals know it and although it is marked you can easily get lost and it’s not wise do walk it in the middle of the afternoon in temperatures approaching 40c.

‘If he did try and walk that way to Symi then that is a big mistake.

‘There are also many troubling questions here. Why did he leave the beach and his wife and friends?

‘Why did he not take his telephone? From the CCTV footage it’s also clear he didn’t stop for a drink in Pedi or take a rest.

‘He seemed to be walking very determinedly, surely it would have been better to stop and have a coffee or some water but no he decided to carry on.’

A local restaurant owner, who asked to be named only as Nikos said: ‘It’s very strange what has happened: where has he gone to?

‘It’s only a small island, and he was wearing bright clothes. The fire brigade, police, and coastguard have been searching for three days and have found nothing.

‘They have had a drone up and seen nothing and they have used thermal images as well.

‘It’s all very strange, the path is difficult, but it is doable, although I would never do it in the heat of the day.

‘One thing I thought was strange is that he had an umbrella, I’ve lived her 40 years and I’ve never seen a guy with an umbrella walking through Pedi ladies yes but not men.’

Another rescuer told MailOnline: ‘We will keep going until we find him; there is no way we will call the search off for at least another week. There is always hope.’