Coronavirus rate of transmission is increasing, says chief government statistician

Crucially, the measure is the most important of the five tests before the lockdown can be eased significantly

The critical ‘R’ rate measuring the spread of coronavirus infections is on the rise again, the national statistician says – raising fresh questions about any lockdown easing.

Professor Ian Diamond told the Downing Street press conference: “That is driven by the epidemic in care homes. That gives us a real challenge.”

The warning came as Dominic Raab, the foreign secretary, said any relaxation of restrictions – to be announced by Boris Johnson on Sunday – would be “modest, small and incremental”.

A reproduction rate of anything above 1 means each infected person is, on average, passing it on to more than one other, but experts agree it must be well below 1 to prevent a second peak of the pandemic.

Crucially, it is the most important of the five tests before the lockdown can be eased significantly. The prime minister himself admitted there is still a “pandemic” in care homes.

Earlier, Professor John Edmunds, from the London School of Hygiene, estimated ‘R’ to be only just below 1 – the figure above which overall cases would be increasing once more – up from 0.6-0.7 two weeks ago.

Asked if he agreed, Professor Diamond said: “Prof Edmunds I think is right that R has probably gone up just a little bit from his last estimates and that is driven by the epidemic in care homes. He would say, and I would not demur from that.”

However, he pointed out that “prevalence” – the actual number of cases – was also crucial in determining how significant any increase was.

But Jonathan Ashworth, Labour’s shadow health secretary, seized on the warning, tweeting: “Many warned care homes were highly vulnerable calling for a credible strategy to protect residents and care workers with PPE and accessible, regular testing.

“If ‘R’ now increasing because of social care surely exposes government failures to implement infection control in social care.”

Mr Raab put the reproduction rate at anything between 0.5 and 0.9, suggesting ministers are struggling for a reliable measure.

Further scientific evidence is being gathered ahead of the announcement the prime minister will make on Sunday evening, with some relaxation possible the following day.

Prof Ian Diamond, the national statistician, revealed he would begin publishing data next Thursday – and then twice a week afterwards – showing what proportion of the population is estimated to have coronavirus.

Mr Raab was forced to fight off accusations that the prime minister had acted recklessly by hinting at a lockdown easing before a Bank Holiday weekend – when no announcement will come before Sunday.

The approach has angered Nicola Sturgeon, who said it would be a “catastrophic mistake” to change the ‘stay home’ message – to ‘stay safe’ – as the government is expected to do.

But Mr Raab distanced himself from reports that, for example, people will be allowed unlimited exercise, saying: “Any changes in the short term will be modest, small, incremental and very carefully monitored.

“If we find, in the future, the R level goes back up or that people aren't following the rules, we must have the ability then to put back measures in place.”

Confirming the existing rules remained “for the moment”, he added: “As people look towards a warm bank holiday weekend, that we continue to follow the guidance in place at this time.”