THE Powys scientist whose modelling led to the original lockdown in March has said that a relaxation of restrictions over Christmas could see coronavirus transmission rates and prevalence “easily double”.

Professor Neil Ferguson, an epidemiologist at Imperial College London, said “individual judgment” is important when deciding whether to see elderly relatives over Christmas.

Speaking on BBC Radio 4’s Today programme, Prof Ferguson, who was brought up in Trefeglwys and attended Llanidloes High School, also said that while indoor mixing would “increase transmission compared with everyone staying at home, not mixing at all”, the decision to relax rules was part of striking a balance around compliance.

Referring to the hypothetical option of a Christmas break during which no household mixing was allowed, the expert said: “What proportion of the population would actually go along with it?

“I think you have to bring the population with you. I think the measures at Christmas … do pose some risks and I think individual judgment is important in deciding whether to see elderly relatives.”

Prof Ferguson’s message echoes Prime Minister Boris Johnson’s statement to the public earlier this week, when he told families they must make a “personal judgment” about the risks to vulnerable loved ones when meeting over Christmas.

Prof Ferguson has previously described the decision to allow an easing of restrictions at Christmas as a “political judgment”, saying that “there will be consequences … some people will die because of getting infected on that day”.

In a set of documents released on Friday, the Scientific Advisory Group for Emergencies (Sage) said “substantial mixing” of people over a short period of time represents a “significant risk for widespread transmission”.

The scientists made their warning in a meeting on November 18 – a few days before the Government announced that there would be a limited relaxation of restrictions at Christmas.

They said: “The prevalence could easily double during a few days of festive season, with further multiplicative increases as new infections go back to their 'routine' networks.”

Mr Johnson confirmed earlier this week that three households will be able to mix from December 23 to 27, but he told families they must make a “personal judgment” about the risks to vulnerable loved ones when forming a Christmas bubble.