The UK will 'definitely' suffer another wave of coronavirus cases, Professor Chris Whitty has warned.
England's chief medical officer predicts that there will be problems with variants, vaccine shortages and outbreaks in schools and prisons.
He said it there would be "bumps and twists on the road" as people across the UK took part in a minute's silence to remember Covid-19 victims after a terrible 12 months.
Speaking at a public health conference organised by the Local Government Association and Association of Directors of Public Health, Prof Whitty today said: "This is a sad day, really.
"The path from here on in does look better than the last year but there are going to be lots of bumps and twists on the road from here on in.
"There will definitely be another surge at some point, whether it's before winter or in the next winter, we don't know.
"Variants are going to cause problems, there will be stock-outs of vaccines and no doubt there will be multiple problems at a national level but also at a local level - school outbreaks, prison outbreaks, all the things that people are dealing with on a daily basis."
Professor Calum Semple, a member of the Government's Scientific Advisory Group for Emergencies (Sage), said he thought a third wave of coronavirus could potentially hit in the summer.
"The concern at present is that in countries where there's less vaccination and a very strong third wave, that's the perfect breeding ground for further variants of concern," he said.
"So, at this point, Britain has got its act together, the concern is as this third wave is going on elsewhere, that will generate new variations.
"Even within Britain there is a likelihood of a third wave in potentially July and August time, when we do unlock society."
Earlier today Health Secretary Matt Hancock said there are currently no plans to put all of Europe on the travel "red list" after the prospect was raised on Monday by health minister Lord Bethell.
The red list currently forces British nationals and people who are normally resident in the UK to quarantine in a Government-approved hotel for 10 days.
Mr Hancock, who spoke to his Spanish counterpart on Monday about whether travel could resume safely, told LBC: "We don't have any plans to do that.
"We do have this red list and the amber list, and at the moment that is working well, so we don't have plans to do that."
He told BBC Breakfast that current border measures were protecting the UK from new variants, some of which have been shown to evade a degree of immunity offered by vaccines.
He added: "The question is whether we'll be able to release any of these measures over the summer.
"I entirely understand people's yearning to get away and have a summer holiday, and we're looking at that question right now as part of the global travel taskforce, which will report in the middle of next month.
"The earliest that will take any steps will be May 17 but, obviously, we're taking a cautious approach because we want any openings that we make to be irreversible."
