Boris Johnson is expected to announce on Tuesday plans for the hospitality sector to reopen from July 4 and set out whether the two-metre social distancing rule in England can be relaxed.

Health Secretary Matt Hancock said over the weekend that England is “clearly on track” to further ease lockdown restrictions after repeated calls to reduce the two-metre rule to one metre.

The Prime Minister is discussing the proposed changes with the Covid-19 strategy committee on Monday afternoon, attended by chief scientific adviser Sir Patrick Vallance and chief medical officer for England Professor Chris Whitty.

He will then outline plans to Parliament on Tuesday for pubs, restaurants, hotels and hairdressers to reopen in England from July 4, and a likely loosening of the distancing guidance to boost the economic restart.

Dr Zeshan Qureshi, lead author of a report on social distancing for Oxford University’s Centre for Evidence-Based Medicine, told BBC Radio 4’s Today programme there was scientific uncertainty around relaxing the two-metre rule.

His team has looked at every study published up to June 17 on Covid-19 and social distancing.

“This one to two-metre distancing, it’s not based on data that we are getting from coronavirus,” he said.

“It is based on historic data, decades and decades old that has been applied to coronavirus in good faith.

“It is based on very old, outdated models of droplet transmission, which assume that large droplets are the route in which infections are transmitted.”

He said more modern studies had shown those droplets are on a “spectrum” and smaller droplets can project up to eight metres.

He said it was possible the virus could be transmitted much further than two metres between people.

“We don’t know what a toxic dose of coronavirus is… we don’t know it’s safe to relax what we’re doing already,” he said.

He added that any relaxation of current measures should be done with very “close monitoring” of the consequences.

There is evidence that “more social distancing is better than less social distancing”, he added.

When asked if the two-metre social distancing rule is going to be reduced, Security Minister James Brokenshire told BBC Breakfast: “There has been a great deal of work that’s been taking place at pace over the last number of days, informed by the science, informed by experience from around the world as well, as to how we can appropriately look at easements and appropriately also reflect on the two-metre rule as well.”

He added the international experience and understanding of the virus had evolved in recent weeks and the decision would be informed by “the best, most up to date science” and medical experience.

On Sunday, the PM said the progress made in the fight against coronavirus during three months of lockdown mean “it will be possible to open up more”.

“The disease is increasingly under control and I just want people to reflect on that important fact,” he added in a Downing Street interview.

Guidance will be published for each sector on how businesses can reduce the spread of Covid-19 when they reopen.

The public are also expected to be warned that the newest relaxation of rules will be the first to be reversed if there are widespread breaches that prompt the virus to spread uncontrollably.

A No 10 spokesman said: “We will not hesitate to put the handbrake on to stop the virus running out of control.”

Downing Street said also said on Monday it would keep Sunday trading rules “under review” following reports it had dropped plans to change them in order to boost the economic recovery.

The Prime Minister’s official spokesman, when asked whether plans to widen Sunday trading had been ditched, said: “We have said we will keep measures such as extending Sunday trading hours under review as they can support shops with social distancing and allow shoppers to buy food and other items more conveniently.”

In other developments:

– Around four in 10 young people who say coronavirus has affected their wellbeing believe the lockdown has made their mental health worse, according to new analysis from the Office for National Statistics (ONS).

– When asked how long they thought it will be before their life returns to normal, just over a fifth (22%) of people aged 60 and over surveyed by the ONS said that it would be more than a year – or never at all.

– The coronavirus crisis should lead to more integrity and less hypocrisy in politics and society, Pope Francis has said in a Radio 4 interview.

– Spain has begun “freely” welcoming Britons without the need to quarantine, in a call for the UK to reciprocate and form a so-called air bridge.

Meanwhile, Labour MP Florence Eshalomi has called on the Government to help the hospitality sector adapt to the changed landscape.

Ms Eshalomi told BBC Radio 5 she had a range of popular sites in her Vauxhall electorate, including the Royal Festival Hall and the Southbank Centre, adding that “maintaining two-metre social distancing is not viable”.

On Sunday, Mr Hancock gave perspex screens, masks and altered seating arrangements as examples of measures to mitigate the risk of spreading coronavirus if the two-metre rule is relaxed.

And he floated the idea that punters at pubs and bars could have to sign a guest book with their names and contact details so they could be swiftly traced if they come into contact with an infection.

Shadow health secretary Jonathan Ashworth said Labour would support a reduction of the two-metre rule “under certain circumstances”, including the strengthening of other protections such as masks.