Boris Johnson says he hopes the two-metre social distancing rule can be reduced - but scientists say it is still the safest approach.
Today the Prime Minister told MPs that he has spoken to experts about reducing it in order to support public transport and the hospitality trade.
But he said advice from the government's scientific advisory group for emergencies (Sage) remains in place.
It comes after landlords warned thousands of jobs would be lost unless the social distancing guidance is halved, because many venues will not be able to reopen.
Mr Johnson told the Commons Liaison Committee: "My own hope is that as we make progress in getting the virus down, in reducing the incidence, that we will be able to reduce that distance, which I think will be particularly valuable in transport and clearly the hospitality sector."
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The PM argued that advice from the scientific advisory group for emergencies (Sage) remains that there's "a very considerable reduction in risk at two metres".
Tory MP Greg Clark pressed for the PM to instruct Sage to review the distance.
Mr Johnson said: "I can not only make that commitment, I can tell you I've already done just that."
At today's daily briefing, Health Secretary Matt Hancock said social distancing measures must remain in place.
He urged the public to carry out their "civic duty" and make a new test and trace system work - saying the only other option is continuing the lockdown.
NHS Test and Trace will officially launch across England on Thursday with the help of 25,000 contact tracers, while an accompanying app is still delayed by several weeks.
People with coronavirus will have their contacts traced under the scheme, which aims to cut off routes of transmission for the virus and control local flare-ups.
Mr Hancock told the daily press briefing: "The big question that we're all working to answer is this: until an effective treatment or vaccine comes through how can we get back to doing more of the things that make life worth living without risking safety or putting lives at risk?
"NHS Test and Trace is a big part - not the only part - but a big part of the answer to that question."
Mr Hancock said that by tracking infected people and isolating their contacts, and by continuing social distancing, the national lockdown could be replaced with individual isolation.
"This is national effort and we all have a role", he added.
"The virus exists only to reproduce - that's its sole biological purpose, to make as many copies of itself as possible.
"If we can thwart that purpose, we can control the virus and ultimately defeat it.
"We must all follow the NHS test and trace instructions as this is how we control the virus, protect the NHS and save lives."