How Dr Clare Bailey must endlessly replay her last goodbye to her husband, when Dr Michael Mosley raised his arm aloft then strode on his merry way... only to vanish into this air, writes IAN GALLAGHER

Dr Clare Bailey was concise and to the point. She noted that it had been three days since her husband – the Mail columnist and TV doctor Michael Mosley – 'left the beach to go for a walk. The longest and most unbearable days for myself and my children'.

Words that were all the more powerful for being unfussy and shorn of hyperbole. Not that anyone would have blamed her for drifting into sentimentality. Not in her state of mind.

As it was, the word 'unbearable' semaphored the pain, offering a window into Dr Bailey's nightmarish new reality. One minute her husband was at her side on a charming Greek island and all was right in their world. Then suddenly he was gone.

How must that feel after nearly 40 years of marriage?

Theirs has been a true partnership, combining a loving relationship with overlapping work commitments. Earlier this year, they embarked on a joint theatre tour and previously worked together, among other things, on their famous 5:2 diet.

What agonies, what memories, must have floated past Dr Bailey's mind's eye these past few days.

And how she must have endlessly replayed their last goodbye, when her husband, a slightly donnish, bespectacled 67-year-old man loved by millions, raised his arm aloft then strode purposefully off on his merry way – only to apparently vanish into thin air.

By all accounts he was in good spirits. Perhaps they were lifted by his first glimpse of Symi the day before he went missing.

Viewed from the ferry, its ash-grey mountains suddenly reveal an arresting vista: a picturesque harbour of coloured neo-classical houses. Next day, a boat ride to a hidden beach, a spot of sunbathing, a swim in invigorating clear water. All would have cheered him further.

Certainly, after telling his wife he would walk to their accommodation rather than return with her and another couple in the boat, he seemed happy.

One witness to his stroll through Pedi, a fishing village, said he seemed to 'cut a jaunty air'.

The English holidaymaker added: 'I recognised him from the CCTV as someone who walked right past me.

'What must have stuck in my mind was his umbrella which I later saw on the CCTV footage in the media. He was using it as a parasol as it was so unbearably hot on Wednesday. Yes, he was sauntering along, seemed fine.'

Mysteries such as this have a habit of throwing up little details that sometimes assume disproportionate significance. Vital clues that turn into red herrings. What then are we to make of reports that after wending his way around Pedi's marina, and after the last CCTV sighting of him, Dr Mosley was spotted apparently minus his purple brolly?

This would apparently have been just as he was about to scale a mountain path under a merciless sun. But then there is much about this case that doesn't make sense.Not least, why tackle the Vroulias mountains in the first place?

One theory is he missed the road to Symi town and thought he might get back on track over the mountains. If he had continued in the same direction, why wasn't he spotted around Agia Marina, where he could have bought more water?

'If he was here we would have seen him,' said a waiter at Agia.

And how treacherous is this mountain route anyway. It is undeniably tricky underfoot. Jagged rocks poke out of unyielding soil from which nothing much sprouts except thistles and stunted shrubs. More likely the danger lies not in the route itself but the heat.

'We've walked it several times and it's not treacherous at all,' said a 70-year-old woman called Sue from Hebden Bridge, West Yorkshire. As she acknowledged, she was speaking as an experienced hiker. 'But it's not a difficult route,' she insisted. 'Which makes his disappearance all the more mysterious.'

Meanwhile, the affable mayor of Symi, Eleftherios Papakalodouka remains convinced that the answers lie in the mountains.

'We are searching an area of around 6.5km and it's very difficult to pass. There are only rocks, no shade, no trees. With 47 degrees heat, you can't survive.'

He said Dr Bailey has been liaising with the authorities, helping the police to identify her husband on CCTV. 'Until they find him, it is agony,' he added.

Asked how long the search would continue, the mayor said: 'There is no chance we will call off the searches but I believe they will conclude somewhere today.'

Dr Bailey's anguish must have been assuaged, if only marginally, by the arrival on the island of the couple's grown-up children. At least two of the siblings joined the search, retracing part of the route their father is thought to have taken on a mountain.

Later, their mother would end her statement with a resolute promise. 'We will not lose hope.' It was a sentiment echoed by a firefighter who trudged forlornly down to Pedi marina after a day spent scouring the mountainside.

'We Greeks believe in miracles,' he said. 'Please don't think it's over yet.'

It seemed to inspire and galvanise the Greek search and rescue teams. Soon a red chopper began endlessly circling the rocky headland where the authorities believe he trudged.

Unsurprisingly it caused a burst of speculation. Were they searching a network of caves known as The Abyss, which sit beneath an outcrop off Agia beach?

Another flurry of excitement. The helicopter was hovering low now. Had he been found? Again though, it all came to nothing.

None of the rescuers had a fixed idea of what might have happened to Dr Mosley. His wife said the search was 'still ongoing' and expressed thanks to the people of Symi, the Greek authorities and the British consulate, all working 'tirelessly' she said, to help find her husband.

Above all else, locals are mystified as to why Dr Mosley hasn't already been found.

'Everyone thought this would be cleared up in hours,' said the owner of a taxi firm in Symi Town, 'The longer it goes on the more outlandish the theories. They are already starting among people who don't know better.'

At a cafe on the nearby harbour some Red Cross volunteers were enjoying cold drinks after finishing their shifts.

'We really thought we would find him when we saw the terrain. Nothing can be hidden up there. It's as if he vanished in a puff of smoke. Either that or he's surprised us all and somehow managed to reach a different part of the island. But without being seen? It doesn't make sense.'

Common among the theories shared privately by the Greek authorities is that Dr Mosley experienced some kind of episode, or medical catastrophe brought on by the intense heat.

Still, though, it doesn't explain why he hasn't been found.

In 2019, Dr Mosley wrote about a holiday with his wife in Cornwall when a dip in the freezing sea temporarily wiped his memory and he ended up in hospital.

'I didn't have any obvious signs of physical or facial weakness, nor was my speech slurred – both telltale signs of a TIA (transient ischaemic attack) and a stroke,' he said. 'I was lucid and the only thing that was obviously wrong with me was the fact that I had no memory of how I'd got there, or what had happened to me.

'Puzzled, the junior doctor went off to fetch a more senior colleague. He did a further examination and gave me the good news that whatever was wrong with me, I had not had a stroke or epileptic attack.

'Instead he said that I had almost certainly experienced something called transient global amnesia, and that it was brought on by cold-water swimming.

'He said it was like a migraine attack, and although my memory had been badly affected, he fully expected it to return to normal within 24 hours.'

He added: 'It goes without saying, I'm glad that my amnesia wasn't anything more serious. And, despite this experience, I'm not put off going for cold-water swims in the future.'

Finally, he added, with what now seems like poignant retrospect: 'But I will make sure that when I do, I always have someone with me.'