Lifting lockdown restrictions for the sake of Christmas would be “throwing fuel on the fire” of the pandemic, a member of the Scientific Advisory Group for Emergencies (Sage) has warned.

Andrew Hayward, professor of infectious disease epidemiology at University College London (UCL), said on Thursday that households mixing at Christmas would “pose substantial risks”.

“We’re on the cusp of being able to protect those elderly people who we love through vaccination and it would be tragic to throw that opportunity away and waste the gains we’ve made during lockdown by trying to return to normality over the holidays,” he told BBC Radio 4′s Today programme.

But Downing Street has said it is Boris Johnson’s “clear intent” for the public to have as normal a holiday as possible.

Angela McLean, the deputy chief scientific adviser, confirmed on Wednesday that the government had been handed advice from experts about how it could lift restrictions for a few days.

Public Health England also revealed it believed for every one day of relaxed rules, an extra five days of “tighter” lockdown would then be needed.

According to The Sun, one option under consideration is a five-day period beginning on Christmas Eve during which households could mix. 

If the rules are loosened for five days, that would mean 25 days of tighter restrictions would have to be imposed.

Hayward said: “Mixing at Christmas does pose substantial risks, particularly in terms of bringing together generations with high incidence of infection with the older generations who currently have much lower levels of infection and are at most risk of dying if they catch Covid.

“My personal view is we’re putting far too much emphasis on having a near-normal Christmas.

“We know respiratory infections peak in January so throwing fuel on the fire over Christmas can only contribute to this.”

England’s four-week national lockdown is due to come to an end on December 2.

The prime minister has said he wants to then revert to a system of local measures.

But Johnson is facing growing opposition to continued restrictions from Tory MPs.

Mark Harper, the former Tory chief whip, said: “We cannot keep living under a cycle of restrictions, expect people to be grateful for being let out to enjoy the festive season, only to impose strict restrictions on them afterwards, causing health problems and destroying livelihoods.”