One of the government’s scientific advisers said he is “worried” about a possible spike in coronavirus infections within weeks.
Sir Jeremy Farrar, a member of the government's Scientific Advisory Group for Emergencies (Sage), said there was a real danger of the virus spreading faster as further lockdown measures are eased from the beginning of next month.
"I would predict, I would guess, that we will start to see a few increases in cases towards the end of June or the first week of July,” he told the BBC’s Andrew Marr show on Sunday.
"We're on a knife edge, it's very precarious the situation, particularly in England at the moment, and I would anticipate we would see an increase in new cases over the coming weeks."
Ahead of the reopening of pubs and restaurants, Sir Jeremy urged people to still be "really cautious, particularly around any events indoors".
He added: "There is no zero risk in any of this. We're not at the stage where the virus has disappeared.
"The restrictions have not changed the fundamentals of the virus. It remains the same virus."
Sir Jeremy also argued that the next three months were "absolutely critical" in the fight against coronavirus in the UK.
"Come the winter, come the reopening of schools, which is absolutely critical, we can anticipate to see rebounds and second waves,” he continued.
"That's the key, using June, July and August really cleverly, making sure we have everything in place and learning the lessons from February and March."
It comes as the hospitality industry is preparing to reopen in a matter of days for the first time since March.
Prime minister Boris Johnson announced earlier this week that Britons can return to pubs and restaurants with “minimal staff and customer contact”.
Johnson also announced two households will be allowed to meet indoors and stay overnight.