More than a third of coronavirus admissions at Norfolk's biggest hospital during one week this month were caused by the newly-discovered variant, Norwich researchers say.

Research from The Quadram Institute, at Norwich Research Park, found the new variant accounted for 45pc of all positive samples in the community in Norfolk in the first week of December. The samples primarily come from community testing - which includes drive-through tests and home kits.

The findings also revealed the mutation accounted for 36pc of new cases at the Norfolk and Norwich University Hospital during the second week this month.

At the James Paget University Hospital in Gorleston and the Queen Elizbeth Hospital in King's Lynn it was detected in 5pc of patients who tested positive for coronavirus.

But a blog post written by researchers says: "There is a time lag between getting infected and being sick enough to require a trip to the hospital for Covid-19, so we would expect the new variant cases to rise in other hospitals across the county in the coming weeks."

Elsewhere, the findings said it appeared a 'distinct' variant had caused the outbreak in Wymondham in November.

Overall, the research said there were at least seven different strains of the virus introduced in Norfolk in November.

But it added: "Some of these introductions will go nowhere, people will get sick, self-isolate and that transmission chain ends."

Concern has been mounting over the new variant, which has led to London and parts of south-east England being rushed into the new Tier 4 at the weekend, effectively cancelling Christmas plans and imposing measures similar to previous national lockdowns.

It comes after Norfolk reported a record high number of coronavirus cases, with the infection rate at 192.8 cases per 100,000 people for the seven days up to December 18.

The report said: "There is no evidence to suggest the new variant causes more severe disease or affects age groups differently to other lineages of the virus.

"However, those that are vulnerable to severe infection (older people and immuno-compromised people) remain vulnerable. If this new lineage is more transmissible, more vulnerable people will catch it faster, putting them and the NHS at risk."

It urged people to follow coronavirus rules such as social-distancing and hand-washing.