It Wasit turns out an understatement.

His persistent fever and cough were just days later to put the prime minister into ST Thomas's Hospital, and from there last night into intensive care.

Intensive care is used the patients that can't be managed on the ward.

So these are patients that are deteriorating or may possibly deteriorate very quickly.

So we would take a patient into the intensive care unit and know that we have all the correct staff.

We have equipment such as ventilators that we can put them on should the need arise.

There is so much still not known about Covered 19 and one of those questions is.

Why do some people become seriously ill while others are fine?

The health secretary and Boris Johnson were infected at around the same time.

Matt Hancock is now back at work, and there is the question, too.

Why do some patients seem to be on the road to recovery and then dramatically worsen?

Average incubation.

Fur covered 19 is five days but can be a CZ long as 14 days.

The majority of people will have a fever and a dry cough, while others may have mild or no symptoms at all but will still be carrying the virus after a week.

Most have recovered.

And then there are those like the prime minister, who develop a more severe infection.

The lungs become inflamed, and they have trouble breathing.

At this point, they are usually taken to hospital and put on oxygen.

A small number become critical, unable to breathe on their own, and this is when they're put on ventilators.

These patients often develop pneumonia, and with oxygen levels in their blood dropping, they can have organ failure and in some cases, sadly, they die.

A Downing Street spokesman said the prime minister was receiving oxygen and breathing without any other assistance being admitted.

Toe I see you, we were told, was precautionary and that he is not on a ventilator.

Dominic Minghella was brought to King's College in south London in a similar condition to the prime minister, and he told us today of the relief once he was given the oxygen, I think there's a kind of crucial moment around.

So day 789 where particularly guys, apparently a reluctant to call for help and It's particularly guys who get this overwhelmingly.

Get this, get themselves into the critical situation.

Um, on Dhe.

So I'm glad that I'm Boris Johnson's gone in, and I'm glad he's near a ventilator whether he needs it or not, because the other thing we know is that you can deteriorate, deteriorate really rapidly.

Um, and he will know that he will know much too much about this virus for his own comfort.

Um, Andi, I'm glad he's in here the best care that they can give him.

The problem for doctors treating the prime minister is there is no cure and little in the way of treatment.

There are trials looking at HIV, rheumatology and malaria drugs, and patients have been given these, but they are not licensed for use and covered.

19.

The factors.

The disease is too new one day.

It is hoped, though, that the research will answer why Boris Johnson and so many like him, end up in intensive care units and why and too many cases.

There are those who simply do not survive.

Take Victoria is with me now, because every day we have been given the official figures for the number of people who have died after testing positive for Corona virus from the Department of Health.

But new data from the Office for National Statistics suggest that the true figure could be much higher.

Health such care correspondent Victoria's just join me in the studio.

It just is rather complicated to explain.

But the point is, the figures that were given every day include time legs.

You know, there are some hospitals that simply don't have time to fill in those forms or they have to tell relatives.

So these figures are incomplete.

Now there is no conspiracy, although I'm sure some people are finding find a good conspiracy in there.

But today, the Office for National Statistics has put together a ll the deaths hospital community care nursing homes on the death certificates and has to say covered 19 or suspected covered 19.

So look at this graph Here.

This is the best measure is up to March the 27th.

This is where the O.

N s figures go too.

So we were given the figure for that day.

Up to that date.

926 people have died.

The O.

N s figures show that the number of deaths was actually 70% higher.

1568 today.

Thehe cumulative figure is the number off 5655 England only now if we had b.

O.

N s figures, that would suggest that the true total is more than 9000 Now this obviously illustrates that the toll is far worse them we're being led to believe.

And again I have to say that this is not a conspiracy.

All countries have trouble recording deaths that they're looking for different ways.

We do it in different ways, but it also makes it.

Then you can see difficult to make comparison would say Where are we compared with Italy or France or or the US?

And we are waiting to for that figure, there's the 20,000 figure off the number of deaths expected if we did the social distancing and closed the schools.

So we have to ask, Are we nearly halfway there or is that for go wrong?

We're joined now by Hugh Montgomery.

He's professor of intensive commits and had University College London.

Thank you very much for joining us, Professor.

What would you What would make you decide to move a patient into intensive care.

So essentially, it's the trajectory of the patients.

We've heard that these patients become a short of auction what we would call my pock sick Andi.

It's partly the level of hypoxia how much oxygen one requires, but also actually the look of the patient.

These people often have very high work of breathing there, often brooding very deeply and very fast.

And those the sorts of patients we worked very closely indeed, because while some remain very stable on others can fall off the perch very quickly indeed, and by very quickly I'm talking minutes half an hour to an hour, and that's why they put in there the same treatment everyone will be getting.

This won't be preferential.

This will be what would happen to anyone who has been a place where, if you decline suddenly be in a place where extra support could be deployed straightaway.

Do you sense that we are reaching the peak of this outbreak?

I mean, a lot of patients seem to be being moved to other hospitals.

Is that a shortage of beds or a genuine sign that we may be getting that?

No, at the moment, I'm not feeling it.

I don't know what the current data are in.

Terms of slowing looked for our sector in north London that there was a bit of a slow down that's now picked up again, and we're into baiting the same number of patients every day.

Now, as we have bean, pretty much so, there's no signs for us of the slowdown.

What's actually happened is that the existing number of intensive care beds were exhausted a long time ago, and trusts expanded up that capacity to take critically or people by opening up beds in operating theatres or out on wards and starting them in a way we wouldn't normally have done.

So we're starving them with instead of one eye to you.

Nurse per bed.

It's now one eye to nurse.

Perhaps six beds with support of others at the bedside wants me to ask you about the Nightingale Hospital.

Is that actually now working on their patients in it or it's still waiting to go.

My understanding is that the first patients will be admitted there today and I've not phoned up to find out it was my understanding there would be patients there by this evening, and it's the right thing to do to prepare that backstop.

I heard it raised that maybe we won't need those beds and so forth.

But if you haven't got the class D built in, then it's not there, and you can't do it in a hurry.

So it was the right thing to do, and we are overflowing.

So our hospitals in North London, many of them are now transferring to expanded capacity in what's known as surgeons Super search centers.

So you see Leitch down the road from us, for instance, taking those.

And once those are beginning to overflow, then the flood will then move down to excel.

Victoria McDonald just now reported that the Office for National Statistics is reporting that the number of deaths could actually be twice what has been officially confirmed.

Would that tally with your experience?

What would explain it?

Yes, I think it probably would.

And it's partly to do with registration off off death.

So there is a process for anyone who has bean bereaved.

There's a process, of course, a filling in a form, the form then being registered in that registered cause of death, then being documented.

So there will be a lank of the O.

N s statistics.

Those of the national registry behind what's happening on the shop floor.

I can't tell you how long that would be, but there will be a lank, I think probably early on as well, there might have bean deaths that people were less aware we'll have bean Corona virus.

We've now got to recognize that pattern of disease really quite well.

So even if the test is negative or someone dies before the swabs back were able to write with confidence that it's growing of our source of suspected Corona virus.

And I think that will also account for the numbers becoming sort of higher a cz the days go by.