Dr Hilary has issued a stark warning over the new South African coronavirus variant.
During today's episode of Good Morning Britain, the medical expert told hosts Charlotte Hawkins, Piers Morgan and Susanna Reid that the new strain is of 'great concern'.
It comes as door-to-door testing across parts of Britain starts today after cases of the South African variant were found in certain postcodes.
The South African variant is more transmissible and so far has been contracted by at least 105 people in England.
"Because it is more transmissible, it will spread more readily, and there are fears it could be a third more resistant to our current vaccinations, so that is great concern." Dr Hilary told viewers.
"And that's why 80,000 people are being asked to come forward and accept PCR tests to find out if it is more prevalent in those areas."
The 67-year-old warned that it is "too late to bottle this one up" and closing our borders would do very little to stop the strain from spreading any further.
But he added that "inevitably" there will be more variants in the future.
He continued: "The only way to prevent more variants coming in is to quarantine everybody, in mandatory fashion, self-isolate them, test them, don't release them until they test negative on more than one occasion.
"Unless the quarantine is mandatory and under surveillance in hotels, people don't quarantine.
"There are 21,000 people coming through our airports every day, they are not being quarantined and they may have the South African variant, they may have other variants."
Dr Hilary told Piers, Susanna and Charlotte that 'it is too early to have sufficient data' as to whether people who were infected and recovered from the original strain could still be infected with the new strains of coronavirus.
"What we know about this new variant it is doesn't seem to increase hospitalisations or be more deadly." He said. "[Infection rates] are coming down but they are still high, that's the critical thing, so there is no room for complacency.
"But the lockdown will certainly be having an effect by now, four weeks on, we would expect to see a fall in cases."
Good Morning Britain will air again tomorrow on ITV at 6am
