England's chief medical officer said he has been left 'saddened' by the proportion of unvaccinated patients in intensive care.

Speaking at a Downing Street news conference, Professor Sir Chris Whitty said 'the great majority' of those who were in intensive care and had not been jabbed were 'not anti-vaxxers in the ordinary sense with some really weird ideas' but had been taken advantage of by those seeking to misinform them online.

Sir Chris said 'misinformation' on the internet, 'a lot of it deliberately placed', about potential side effects from jabs was fuelling fears about whether Covid-19 was important enough to warrant vaccination, leading to vaccine hesitancy.

Whitty also claimed that people were being misled as to whether the vaccines were effective against the disease.

'Insofar as I am frustrated it is simply people deliberately trying to scare away fellow citizens from something that is potentially going to be life-saving for them,' he said.

'In the end, it is the job of health professionals not to get frustrated but simply to say, look, let's go through all of your questions properly and systematically and say which ones are fair and which ones as in many cases, are really completely untrue.'

Prime Minister Boris Johnson said it was 'absolutely crazy' that people were ending up in intensive care with Covid because they had not been vaccinated.

'How absolutely crazy it is, absolutely crazy, that there are two million slots this week for people to get vaccinated and yet the majority of people in ICU for Covid are not vaccinated – 61%,' he told the press conference.

'It is sad but it is also a huge opportunity for us to correct it.'

Mr Johnson added: 'There are still almost nine million people eligible, who haven't had their booster.

'It's absolutely heartbreaking that as many as 90% of those in intensive care with Covid have not had their booster, and over 60% of those in intensive care who have Covid have not had any vaccination at all.

'People are dying needlessly because they haven't had their jabs, they haven't had that booster.'

Sir Patrick Vallance, the chief scientific adviser, said there were 'extraordinarily high levels of infection at the moment' in the UK, and claimed there was 'no evidence' that the Covid spread in London has reached the peak.

'Whilst it may be the case that in the younger age groups it is flattening off or possibly beginning to come down, it's still going up in the older age groups,' he said.

'I think it would be very wrong to suggest that there's a peak which means it's all over in London.'

The press conference was held on the day a further 218,724 lab-confirmed Covid-19 cases were recorded in England and Scotland.

It was the first time the daily recorded figure has passed 200,000, though the number will have been inflated by some delayed reporting from over the holiday period.

The Prime Minister said there is a good chance the nation can 'ride out this Omicron wave' without having to bring in further Covid restrictions, but did not answer widespread calls to cut the isolation period for Covid patients from seven to five days.

In today's Downing St. briefing, Mr Johnson said now is the moment for 'utmost caution' and made no mention of any plans to reduce the Covid isolation periods, despite admitting that Omicron is milder and cases are not translating into the same intensive care demand as previous waves.

The current isolation period in Britain is set at a minimum of seven days, providing a Covid positive individual can test negative on two lateral flow test results at least 24 hours apart on days six and seven.

The PM's comments came amid a torrent of calls from business leaders and health experts alike to reduce the isolation period to avoid a 'lockdown by default' as industries across the nation face forced closures due to staff absences.

Experts claimed that cutting the isolation period to five days would save the UK economy £300million this month while the Centre for Economics and Business Research estimated that the current rules will cost the country £1 billion, equal to 0.5 per cent of monthly GDP.

Meanwhile, Professor of Medicine Paul Hunter told Sky News today that there is a strong argument for cutting the isolation period of Covid positive individuals to five days as the greatest risk of transmission comes from two days before to three days after someone becomes ill.

'I think the balance of evidence is that really, most infections are transmitted in the two days before to three or four days after somebody becomes ill,' he said.

'At the moment, much of the pressure is from keeping people off work, some of whom won't necessarily need to be off work.'