Coronavirus: Growth in infections may be slowing, largest COVID-19 study in England suggests

Research by Imperial College London and Ipsos Mori showed the R number, a key indicator which shows the coronavirus reproduction rate, fell from 1.7 to 1.1 since the beginning of the month.

The director of the REACT study says this could mean that efforts like the "rule of six" and local lockdowns may be effective in slowing the virus - but also stressed the prevalence of the infection was still "the highest that we have recorded to date".

The figures showed around one in 200 people were infected with coronavirus.

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Professor Paul Elliot said: "While our latest findings show some early evidence that the growth of new cases may have slowed, suggesting efforts to control the infection are working, the prevalence of infection is the highest that we have recorded to date.

"This reinforces the need for protective measures to limit the spread of the disease and the public's adherence to these, which will be vital to minimise further significant illness and loss of life from COVID-19."

The most recent data was taken from tests on 80,000 volunteers between 18-26 September, and compared to a previous analysis from 24 August to 7 September.

It comes after the government's chief scientific adviser Sir Patrick Vallance warned the country on Wednesday evening "we don't have this under control at the moment".

Boris Johnson warned that in order to avoid the country going back into a national lockdown was for everyone to "follow the guidance".

The most recent figures from the government's scientific advisory board SAGE put the R number between 1.2 and 1.5 as of an announcement on 25 September.

SAGE updates their number every Friday.

The Imperial study also revealed that one in 100 of people aged from 18-24 were infected - and that age range has the highest rate of any group.

It comes as at least 45 universities reported they had COVID-19 cases, according to Sky News analysis.

The full Imperial and Ipsos Mori study will be published next week.

Analysis: The epidemic is still on a knife edge

By Thomas Moore, Sky Science and Medical Correspondent

This latest snapshot of the epidemic suggests the measures to control the virus are having an effect.

The R number, the measure of how quickly the virus is spreading, has fallen sharply - down from 1.7 in the first two weeks of September to 1.1 more recently.

And cases, which were doubling every week, are now probably doing so every 10-14 days.

The samples were taken from more than 80,000 people across England, whether or not they showed symptoms, so it is a very powerful snapshot of what the virus is up to.

And significantly people were tested from the 18 September, four days after the Rule of Six was brought in, up to last Saturday.

It's impossible to say whether it is the government controls or the publicity over the sudden rise in cases that has slowed the spread.

But, and this is an important but, the epidemic is slowing from a very high number of cases.

One in 200 people are now infected - one in 100 young people - after that explosive spread of the virus at the end of the summer holidays.

Those are huge numbers. And remember the epidemic is still growing, though at a much slower rate.

More worrying still is that the virus is spreading to more vulnerable people. The infection rate in the over 65s has increased by seven times in a fortnight or so.

That will mean a rise in hospital admissions and deaths.

The epidemic is still on a knife edge.

There is no doubt that we will be living under the current restrictions for some time to come.

But if these results are confirmed on Friday by an Office of National Statistics study of infection rates it will make a further tightening of the controls outside the hotspots less likely, for now at least.