Despite the glad tidings, it is important to remember this is all about baby steps

Yesterday Boris Johnson pronounced the words that owners of pubs, restaurants, hotels and businesses across the country had been longing to hear.

As of July 4, the “two-metre” rule would be lifted. Instead, in situations where such distances between people were not practical, other measures – such as avoiding face-to-face seating, and use of protective screens and face coverings – must be imposed, according to the new guidance.

Families will be allowed to meet another household, in homes, restaurants, pubs and bars.

Throughout the Covid crisis, ministers have insisted that they have been led by science. But what is the science to support such changes?

In making the announcement, Mr Johnson highlighted the low infection rates across the country. Despite increases in numbers tested, positive cases have fallen by 70 per cent between mid May and mid June. Four weeks ago, an average of one person in every 400 in the community had Covid.

The latest figures suggest the risk is now one in 1,700, with the rate of new infections declining by between two and four per cent daily. And death rates from Covid are dropping in every age group, with 15 fatalities recorded for the UK on Monday.

Meanwhile, the Government’s review of the two-metre rule concluded that with mitigations – such as protective screens and face coverings – the risks of infection at one metre are broadly equivalent to those at two metres. The decision followed advice from Sage – the Scientific Advisory Group on Emergencies.

At the start of this month a study in The Lancet found that the risk of infection was 1.3 per cent at two metres or 2.6 per cent at one metre.

But two weeks ago, Sage’s Environmental and Modelling group said this did not consider the positioning of the person – meaning the way they were facing – nor how the virus was likely to be transmitted.

Crucially, it concluded that sitting within one metre of a person side-byside or back to back, carried a similar risk to facing a person at two metres, provided an environment was properly ventilated, paving the way for the change in stance. It also set out a series of mitigations – such as the use of screening and minimising the time in contact, to reduce the risk.

Yesterday the Government’s scientific advisers injected a heavy dose of caution – urging members of the public to keep a two-metre distance whenever possible.

Prof Chris Whitty, the Chief Medical Officer for England, said there were “39 steps” people could take to minimise their risks, including handwashing, meeting outdoors when possible, and physical barriers.

“No decision is risk-free; this is about a balance of risks,” he said.

With reference to current infection rates, he said: “What goes down can go up. Winter, for example, may mean we have to increase some of the measures.

“This is going to be a long haul,” he warned. “I would be surprised – and delighted – if we were not in this current situation through the winter and into next spring”.

Noting that current infection levels meant there were still an estimated 33,000 infected people in the country, Prof Patrick Vallance, the Chief Scientific Adviser to the Government, noted that the rates were “flattening off – not going right down to zero.”

He noted: “It is important to remember that infection is still here.”

In a letter published to The BMJ, the presidents of a number of Royal Medical Colleges said that a second wave of Covid-19 was a “real risk” in the UK.

Last night, a number of scientists said that an effective test, track and trace system was needed to support the changes.

Some said that the decision on relaxation should not have been taken until the new cases of infection had reached “the hundreds, not the thousands”.

But other scientists said that the right mitigations, combined with responsible behaviour by the public, were key to the success of the new freedoms.