A doomsday new Covid variant that could kill UP TO one in three people is a 'realistic possibility', according to the Government's top scientists.
Documents published by the Scientific Advisory Group for Emergencies (SAGE) today warned a future strain could be as deadly as MERS — which which has a case fatality rate of 35 per cent — could be on the way.
No10's expert panel It said the likelihood of the virus mutating is highest when it is most prevalent — as is currently the case in Britain.
And a downside of Britain's hugely successful vaccine drive, it appears the country's greater levels of immunity could help speed up the process.
Scientists said Britain should bring in booster vaccine doses over the winter, minimise new variants coming from abroad and consider culling animals — including minks and even cats, which can harbour the virus — to prevent the mutant strain occurring.
A doomsday new Covid variant that could kill one in three people is a 'realistic possibility', according to the Government's top scientists
Scientists unveiled the threat of a super mutant variant in a paper looking at potential scenarios that could emerge in the not-so-distant future.
Experts said a future strain could be resistant to vaccines if it came about by the jab-resistant 'South Africa' Beta variant combining with the more transmissible 'Kent' Alpha or 'India' Delta variants.
The process — known as recombination — could lead to a strain with 'increased morbidity and mortality'.
The team admitted vaccines should work unless there was an extra-potent mutation that rendered jabs much less effective at blocking serious disease — which many experts say is unlikely.
But they said the extra lethality would be expected 'even in the face of vaccination since vaccines do not provide absolute sterilising immunity.'
The prospect of a deadlier variant is a 'realistic possibility' and would have a huge impact on the UK's death toll moving forward, the scientists said.
And experts and politicians have warned the damning report shows the Government 'must not be complacent' as Britain appears to be coming out its current third wave of the pandemic.
Dr Philippa Whitford, vice-chair of the All-Party Parliamentary Group on Coronavirus, said: 'This report, which should have sent shock waves through the UK Government, was instead quietly snuck out among a glut of reports during parliamentary recess.
'Recommendations and comments made by SAGE bring home the simple reality — that we have not yet "defeated" this virus.
'The UK only donated its first vaccine doses internationally this week and, unless there is a rapid increase in global production, through sharing knowledge and technology, it simply will not be possible to vaccinate the world and bring the pandemic to an end.
'Without stricter border control measures we risk importing vaccine-resistant variants while uncontrolled spread here could lead to yet another UK variant.'
The Scottish National Party MP: 'The