Dr Marc Baguelin from Imperial College London, who sits on the Scientific Pandemic Influenza Group on Modelling (SPI-M), a sub-group of SAGE, said the premature opening of the hospitality sector would lead to a 'bump' in Covid-19 cases.
Speaking yesterday (21 January) on BBC Radio 4's World at One programme, he said: "We looked at the partial reopening and the increase in the R number - it will generate an increase in the R number - the extent of which we don't know really.
"Something of this scale, if it was to happen earlier than May, would generate a bump in transmission, which is already really bad.
"So you have a lot of pressure on hospitals, you will have another wave of some extent.
"At best you will keep on having a very, very unsustainable level of pressure on the NHS."
Modelling by researchers from Imperial College London and the Universities of Edinburgh and Warwick indicates that a more gradual relaxation of controls is far less risky, and could provide an exit without overwhelming the health service.
It is understood that the Government plans to discuss the prospect of ongoing restrictions - including limits on capacity, operating table service only and imposing curfews - with businesses and hospitality leaders in the coming weeks, to gauge both the economic and behavioural impact of maintaining such restrictions once hospitality is given the green light to reopen.
In the wake of Baguelin's comments yesterday, Loungers chairman and co-founder Alex Reilley, who told BigHospitality earlier this week that he feared the sector could become stuck with some operating restrictions for years to come, tweeted: "I get that scientists have to do their thing, but surely there has to be a point where even they accept that living life to the full, with risk, is infinitely more preferable to life being just about avoiding death."
Earlier this month it was reported that a Government source had touted the early May bank holiday as a 'realistic' reopening date for the sector.