Boris Johnson has commissioned a review into the 2m (6ft) social distancing rule, following calls to scrap it.
Businesses and some of Mr Johnson’s own MPs have warned that large parts of the hospitality industry will not be viable with the 2m coronavirus rule in place.
The review will aim to be completed by 4 July, when pubs and restaurants could open at the earliest in England.
But former Tory leader Sir Iain Duncan Smith questioned the need for a review, saying “the evidence is already there”.
“Whether there is a review or not, it will come down to a political judgment for the prime minister to make,” said Sir Iain, who has previously said the 2m rule will delay the economy recovering.
“He needs to make the decision now for the good of the economy. If there is to be a review, it should be swift.”
The review, which was first reported in the Mail on Sunday, will take evidence from scientists as well as economists.
Currently, the UK government advises people to stay 2m apart from others to avoid spreading the coronavirus.
This is further than the World Health Organization’s recommendation of at least 1m (just over 3ft), and some other countries like France and Denmark. But the UK government’s scientific advisers say that being 1m apart carries up to 10 times the risk of being 2m apart.
Some bars, restaurants and pubs say they will be unable to make a profit if the 2m guidance is still in place when they reopen. Tourism firms have also warned of tens of thousands of job losses unless the distance is shortened.
Kate Nicholls, the chief executive of the industry body UK Hospitality, says that with a 2m rule, outlets would be only able to make about 30% of normal revenues, whereas 1m would increase that to 60-75%.
Sir Graham Brady, the chairman of the 1922 committee made up of backbench Conservative MPs, welcomed the review and said a move to 1m would be “essential”.
It comes as the number of people who have died with coronavirus in the UK increased by 181 taking the official total to 41,662, latest government figures on Saturday showed.
The 2m distance has been implemented by all nations of the UK, which have their own powers over restrictions. But so far, political leaders have rejected calls to relax the 2m rule.
Earlier this week, Scotland’s chief medical officer Dr Gregor Smith said the evidence was “incontrovertible” that the risk of transmitting the virus increased the closer you got to someone.
He said it was a “balanced and sensible precaution” to ensure transmission is reduced.
And Northern Ireland’s First Minister Arlene Foster said the medical advice suggested 2m apart was the “safest place to be”.
While pubs, bars and restaurants could open in England from 4 July, no date has been given in Scotland, Wales or NI.
On Saturday, millions of people in England and Northern Ireland were able to break the 2m distance with some loved ones after the government allowed people who live alone and single parents in England to form social bubbles with one other household.
Meanwhile, from Monday, all non-essential shops in England will be allowed to reopen – as long as they enforce the 2m guidance among shoppers and staff.
In Northern Ireland, all shops were allowed to open from Friday. No dates have been set for the reopening of non-essential shops in Scotland and Wales, although each country has set out its planned stages for lifting lockdown.
The UK government has repeatedly said it is constantly reviewing its coronavirus lockdown guidance.