Introducing a UK-wide lockdown to deal with the threat of the Omicron variant cannot be ruled out, although the current threat is unclear, Professor Neil Ferguson has said.

The former Llanidloes resident, now a professor at Imperial College London whose data was instrumental to the UK going into lockdown in March 2020, said the variant was concerning but it was still unknown what its impact will be on severe disease.

He suggested people may be told to work from home in the near future as Omicron is spreading fast, with the variant set to take over from the Delta strain before Christmas.

Speaking in a personal capacity, he told BBC Radio 4’s Today programme: “Certainly case numbers of Omicron are doubling at least every three days, maybe even every two days at the moment, so it’s accelerating very fast and put that in context, it’s the same if not faster than we saw with the original strain of the virus in March of last year. So it is a concern.

“It’s likely to overtake Delta before Christmas at this rate, precisely when is hard to say.

“We’ll start seeing an impact on overall case numbers – it’s still probably only 2%, 3% of all cases so it’s kind of swamped, but within a week or two, we’ll start seeing overall case numbers accelerate quite markedly as well.”

Prof Ferguson said the peak of this wave of infection will be in January if no measures are taken to slow it down.

“So if you don’t do anything at the current time, it will most likely be sometime in January,” he said.

“But I think the key question is whether the country decides to adopt measures to either slow it down or try to stop it and that will critically depend on really the threat it poses in terms of hospitalisations.

“At the moment, we don’t really have a good handle on the severity of this virus, there’s a little hint in the UK data that infections are a little bit more likely to be asymptomatic, but we really need to firm up that evidence at the current time.”

Asked whether people should be told to work from home, he said: “It will be up to the Government to decide what to announce in the coming days and weeks.

“There is a rationale, just epidemiologically, to try and slow this down, to buy us more time principally to get boosters into people’s arms because we do think people who are boosted will have the best level of protection possible, but also to buy us more time to really better characterise the threat.

“So if you imagine a kind of Plan B Plus with working from home might slow it down – it wouldn’t stop it but it could slow it down, so it’s doubling rather than every two or three days, every five or six days.

“That doesn’t seem like a lot, but it actually is potentially a lot in terms of allowing us to characterise this virus better and boost population immunity.”

Regarding lockdowns, Prof Ferguson said it was very difficult to rule out anything, adding that we “haven’t got a good enough handle on the threat”.

He added: “Clearly, if the consensus is it is highly likely that the NHS is going to be overwhelmed then it will be for the Government to decide what what he wants to do about that, but it’s a difficult situation to be in of course.”