Britain is on course to be "completely back to normal" by the end of the year, a top scientist has said.

Social distancing could be scrapped on June 21, the date the government provisionally set to end all legal restrictions imposed by the pandemic.

But it is still unclear exactly when life will totally return to normal, after warnings some strict guidance could last beyond that final date in the lockdown roadmap.

But Professor Graham Medley believes life could be back to normal by the end of the year, provided a Covid variant that dodges the vaccine has not emerged by then and that booster jabs are readily available.

Across the country the Government said on Tuesday that a further 20 people had died within 28 days of testing positive for Covid-19, while an extra 2,474 cases were confirmed.

It brings the grim official total to 127,629 and follows months of lockdown.

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Speaking on BBC Radio 4's Today programme, Professor Medley, chairman of the Scientific Pandemic Influenza Group on Modelling group, which advises Government, said the country may be back to normal by the end of the year if there were limited threats from variants.

He said: "If vaccines continue to work, and we don't have some nasty variants, then potentially we could be completely back to normal by the end of the year.

"But, on the other hand, if there are variants, if the vaccines wane, so the impact wanes and we aren't able to get boosters, then we could have been in a very different position."

Earlier, he said the country was now in its best position, saying: "We're in the best position that we've been in the whole epidemic, prevalence is low, vaccines are working.

"I think the risks going forward, you can think of them in two ways: one is the risk to each individual and the other is the risks to the population, so essentially having to go back into a lockdown again.

A person receives an injection
Millions have been vaccinated already as the inoculation drives continues at pace
Professor Graham Medley, from the London School of Hygiene and Tropical Medicine
Professor Graham Medley, from the London School of Hygiene and Tropical Medicine

"Both of those are low but there remain challenges in the sense that we don't know what the virus is going to do in terms of the future and it's quite likely that it will start to increase together and start to transmit, and the question is whether the vaccines can hold it."

He said there will "inevitably" be a third wave of infection "but whether that translates into hospitalisations, I think is the big question. And that's still uncertain.

"I think we've lost the kind of projections that we had back in February, (they) had some really quite scary numbers in, but they were based upon the fact that the vaccines might not work, but now we know they do."

The mass inoculation drive against Covid continues at speed and government data up to May 10 reveals that there have been about 35.5 million first doses and more than 18 million second shots.

It comes amid concern over the Indian variant with recent figures showing that 520 infections had been discovered up to May 5, a rise of 318 from the seven days before that.

On Monday a raft of restrictions will be lifted as part of Boris Johnson's roadmap out of lockdown.