Somehow it was typical of Boris Johnson to drag himself from his sick bed to the steps of Downing Street and to defy the cold by declining to wear an overcoat.

His eyes had the tired and shot look of a man struggling with illness, his unshaven face was pallid and he seemed to have lost weight.

But he remained stoically upright as he joined in the mass applause for the NHS and if the usual ebullience was missing there was at least a flicker of determination.

This was the first sighting of the Prime Minister on his feet for seven days after succumbing to the coronavirus and his appearance was in stark contrast to that of Health Secretary Matt Hancock, who has made a far swifter recovery from the symptoms.

Somehow it was typical of Boris Johnson to drag himself from his sick bed to the steps of Downing Street and to defy the cold by declining to wear an overcoat. But he remained stoically upright as he joined in the mass applause for the NHS (pictured)

At 41 Mr Hancock is 14 years the PM's junior and it is impossible to know if he contracted a milder version of the illness.

All the same, Mr Johnson's washed-out look triggered alarm on social media about just how unwell he has been.

It may also explain why some 12 hours later the Prime Minister felt it necessary to give an update on his condition in a video message.

In it he said he was still suffering from a high temperature – which he took himself – and so was remaining in self-isolation.

Mr Johnson's washed-out look triggered alarm on social media about just how unwell he has been. It may also explain why some 12 hours later the Prime Minister felt it necessary to give an update on his condition in a video message (pictured)

But he also insisted that he was feeling better. For eight days Boris has been quarantined from other ministers and officials as he has fought the virus.

According to sources, he has spent a lot of time sleeping as extreme exhaustion is one of the key features of the illness. One says: 'It has hit him hard, really slammed him but it's in his nature to put the bravest face on it.'

In the videos posted by No 10 he has looked worse as the week has gone on. However, he has manfully appeared to chair every single Covid Cabinet meeting – at 9.15am each day using the Zoom video conferencing app – since the diagnosis.

On Wednesday, by all accounts, he even read ministers and officials the riot act over the testing fiasco. This is both admirable and characteristic as he has promised the nation he will personally lead the fight against the pandemic. But is it wise?

Might he have made a fuller recovery had he concentrated on his own health? This is not the Johnson way, of course. So how has the prisoner of Downing Street been getting on?

At 41 Mr Hancock (pictured) is 14 years the PM's junior and it is impossible to know if he contracted a milder version of the illness

In fact he has adapted quickly to the restrictions the illness has imposed on him. Food is brought on a tray from No 10 and left outside the ground floor office in No 11 which he is using.

The internal doors between No 10 and No 11 are closed and officials have moved tables against them to block them completely.

His office, normally used by Chancellor Rishi Sunak, is out of bounds to any visitor, as is his bedroom. No housekeepers are permitted to tidy the room. For a man used to the company of others, solitary confinement has been hard to adjust to.

Perhaps his greatest challenge has been coping without the reassuring presence of Carrie Symonds, his pregnant partner, who has been self-isolating away from Downing Street.

Since posting a picture of herself with the couple's dog Dilyn on her Instagram account, Carrie, 32, has not been active on social media.

At one stage she was thought to have been at Chequers and she has been seen at her flat in south London.

Downing Street declines to say where she is or how she is. At the same time no one is putting a timescale on Boris's recovery. A friend says: 'He is fit and strong and he will get over this.' When, he will re-emerge in harness is, however, a matter of conjecture.