Confusion over the true scale of England's second wave was sparked today as one study claimed there are now more than 100,000 new cases every day but another put the figure at only half of that.
A Government-funded study by Imperial College London estimated that 96,000 people are catching Covid-19 in England every day and that the outbreak is doubling in size every nine days, piling more pressure on ministers to act to prevent another crisis.
But research also published today by the University of Cambridge estimates that the true number of daily cases is more like 55,600 and the doubling time 17 days.
The two reports present a confusing picture, with Imperial suggesting London is the worst-hit region in England with an reproduction rate (R) of a staggering 2.86, while Cambridge suggests the capital actually has the slowest outbreak in the country, with an R of 1.04.
Testing by the Office for National Statistics (ONS) last week suggested that there were 35,200 new cases per day in the week up to October 18, putting it closest to the Cambridge prediction. This is expected to rise again in the next report which will be published tomorrow.
Official testing by the Department of Health shows an average of 22,000 people are testing positive for Covid-19 each day across the UK, although many more people will have the disease but never get tested because they do not have any of the tell-tale symptoms.
Both teams of scientists say there are major uncertainties in their studies, which are based on statistical modelling of test results.
Although the two present conflicting pictures of the outbreak, both show tens of thousands of people are getting infected every day and the epidemic is growing across the south of England, which has largely escaped any tough local lockdowns.
The University of Oxford's Professor James Naismith, not involved with either study, said: 'I would emphasise that taking these studies together or individually, we can be almost certain that we will see an increase in the number of deaths per day from Covid-19 over the next few weeks and each death will represent a tragedy for the families and friends left behind.'
The 'Nowcast' by Cambridge University researchers estimates that around 55,000 people are catching the coronavirus every day in England (left), compared to a peak of more than 430,000 a day at the peak in March. It suggests the outbreak in London (right) is considerably smaller than a separate study by Imperial College London that suggested the R rate is 2.86
Cambridge University's 'Nowcast' of the current situation in England estimates that there were 55,600 people catching Covid-19 every day as of October 15, compared to 433,000 at the peak on March 23.
It claims that R rates across the regions vary from a low of 1.04 in London to a high of 1.42 in the South West.
In contrast, the Imperial study, named REACT-1, claims there are 96,000 people catching the virus every day. It does not give an official estimate of the number of infections in March and April.
The R rates in the REACT study have a wider range, stretching from a low of just 0.57 in the North East, meaning the outbreak is actually shrinking there, compared to a considerably higher 2.86 in London.
Professor James Naismith, who is a statistician at Oxford, said: 'Nowcasting is an important study from a well-regarded expert group. The headline numbers are rather different than the REACT survey, an equally well regarded expert group.
'These studies use different data and methods to estimate the daily number of new infections and the doubling time in England.
'However, both this group and the REACT group are very careful to estimate the uncertainty in their numbers. For something moving as quickly as Covid19, there is always going to be uncertainty. This is the scientific process, the 95 % confidence intervals from each study for new cases per day are REACT (86, 000 to 105, 000) Nowcast (38,400–81,600).
'These studies and the ONS data tomorrow will be extremely useful in understanding where we are...
'As a scientist I note the trend in other counties, the virus is spreading rapidly. I would therefore expect, but do not know, that the virus will behave similarly in the UK. The REACT survey supports this view. The data from the Nowcasting however indicate that although the virus is growing it is doing so more slowly, giving some hope that we might peak soon.'
Imperial's REACT study, in contrast to Cambridge's Nowcast, predicted that the virus is spreading fastest in London. It claimed the R rate in the capital is almost as high as three and infections are doubling every three days, compared to a national average of 1.6 and cases are doubling every nine days.
It predicted the R rate — the average number of people each carrier infects — is higher than two in London, the South East, East and South West, which have mostly escaped any tough local lockdowns.
And of the entire south of England, London has the highest prevalence of coronavirus at 0.89 per cent, suggesting more than 80,000 of the city's nine million residents were infected at any given moment.
A 'Nowcast' update from statisticians at the University of Cambridge estimates that the R rates for England's regions, based on data up to October 15, are as follows:
N. East & Yorks
East of England
79.5 days days
The REACT study by Imperial College London estimates England's regional R rates to be as follows:
Yorkshire & Hbr.
East of England
-8.8 days, halving
4.7 dayssonos sonos One (Gen 2) - Voice Controlled Smart Speaker with Amazon Alexa Built-in - Black read more
Academics claimed the R rate in London may be 2.86, meaning those 80,000 people carrying the virus at the time of the study could be expected to infect another 229,000. The possible range of the rate — which must stay below if an outbreak is to shrink — is between 1.47 and 4.87, they estimated.
The entire city is in a Tier Two local lockdown, meaning people are banned from meeting indoors with anyone they don't live with, except at work. Infection rates vary across the 32 different boroughs – from 223 positive tests per 100,000 people in Ealing over the most recent week, to 103 per 100,000 in Lewisham.
Government sources fear London and swathes of the south will soon be thrust into Tier Three, saying it was a matter of 'when, rather than if'. Under the toughest measures, residents would be banned from socialising with other households and pubs would shut unless they serve substantial meals.
But one MP today warned moving into Tier Three would kill struggling businesses off completely. Tory London mayor candidate Shaun Bailey told MailOnline: 'We can’t let London grind to a halt or let our eco-system fail. This is a matter of livelihoods as well as lives.'
Scientists behind Imperial's study, funded by the government, came out in favour of a national lockdown, which has now been adopted in France for a second time, and said the results show that current social distancing rules aren't doing enough; Britain, they said, should 'think about changing the approach'.
'I think what our study shows is there would be genuine benefits to some kind of national policy,' Professor Steven Riley, an infectious diseases expert at Imperial College told Radio 4's Today this morning.
'We could prevent the pattern in the South turning into the current pattern in the North and bring about a reversal in the North as quickly as possible.
'If we're going to end up using those restrictions that have been brought in elsewhere in Europe today and yesterday... we should think about timing. And sooner is better than later for these.
The study found that the virus' reproduction 'R' rate - the average number of people each Covid-19 patient infects - was 1.6 across England in the most recent week, compared to 1.16 in the previous round. The R is thought to be hovering between 1 and 1.5 in the north and greater than two in the South East and South West. In London it's estimated to be nearly three
'There has to be a change. The rate of growth that we're seeing in these data is really quite rapid, so one way or another there has to be a change before Christmas.
'We've fairly reliably measured a slight decrease in R in our interim round five [the last part of the study]; now we have measured a slight increase in R, and the slight increase in R means that current measures are not sufficient.'
The research was based on 85,971 swab tests done across England between October 15 and 26, of which 863 were positive. Using this information the researchers calculated around 1.28 per cent of the population is infected.
Rates of positive tests in London show some boroughs have comparable numbers of infections per person than the national average – 230 positive tests per 100,000 people in the week ending October 23 – while others have fewer than half as many.
The Government's Scientific Advisory Group for Emergencies (SAGE) piled fresh pressure on Boris Johnson to impose tougher restrictions after it warned up to 85,000 people could die in a second wave of the disease. Leaked SAGE projections made in the summer suggest that under a 'reasonable worst case scenario' daily deaths could remain above 500 for three months or more, potentially lasting into March next year
Scientists say the coronavirus spreading faster in London than anywhere else in England. The capital currently has Tier Two lockdown rules which ban people from socialising indoors
Ealing, Hammersmith and Fulham and Kingston upon Thames, all in the west of the city, have rates higher than 200 cases per 100,000 – but none have as many as England as a whole.
Croydon, Greenwich and Lewisham, in the south and east of the city, have fewer than half as many cases as the national average, however, with a per-person rate lower than 115 per 100,000.
The city was lumped under the same rules because, Mayor Sadiq Khan said, the population moves around so much that it would be too difficult to try and