The UK’s high death rate is pinned to the fact the coronavirus epidemic started in the country much earlier than scientists predicted, Professor Neil Ferguson has said, as he acknowledged care homes have been poorly protected.

Prof Ferguson, who dramatically quit as a Government adviser last month after it was revealed he allowed a woman he was seeing to visit his home during lockdown, said it was now clear hundreds if not thousands of people entered the UK in late February and early March even before the UK had got its surveillance systems set up.

In a frank admission to the House of Lords Science and Technology Committee, Professor Matt Keeling, of the University of Warwick, also suggested that modellers had “dropped the ball” with regards to how Covid-19 would spread through care homes.

Both scientists were asked by peers what may have been done differently during the course of the epidemic, looking back.

Prof Ferguson, of Imperial College London, said genetic data now showed that most transmissions in the UK originated in Spain and, in some cases, in Italy.

“We had been worrying about import of infections from China… other Asian countries, maybe the US,” he said.

“But it’s clear that before we were even in a position to measure it, before surveillance systems were set up, there were many hundreds if not thousands of infected individuals came into the country in late February and early March from that area (Spain and Italy).

“That meant that the epidemic was further ahead than we anticipated.

“It explains some of the acceleration in policy then, but it also explains to some extent why mortality figures ended up being higher than we had hoped.”

He said the UK was “much more heavily affected” than modellers anticipated, adding: “That’s one of the reasons we have, if not the largest, one of the largest epidemics in Europe.”

He continued: “Going forward, what the models say is that we have limited room for manoeuvre, that this is a highly transmissible pathogen.

“We’ve reduced transmission by about 80%, but to maintain control we need to keep that transmission suppressed by about 65% or so.

“So we have a little bit of wiggle room, so it will be a learning experience as to how we allow society to resume while maintaining control of transmission.”

Prof Ferguson also said he was “shocked” at how badly care home populations were protected globally.

Asked about what could be done in future, he said: “If we had done a better job, or did do a better job, of reducing transmission in closed institutions like hospitals and care homes, we would have a little bit more room, wiggle room as it were.

“The infections in care homes and hospitals spill back into the community, more commonly from the people who work in those institutions.

“So if you can drive the infection rates low in those institutional settings, you drive the infection lower in the community as a whole.”

Prof Ferguson told peers that the number of cases will probably remain “flat” until September.

He said: “I suspect that under any scenario, the level of transmission and number of cases will remain relatively flat between now and September, short of very big policy changes or behaviour changes in the community.

“The real uncertainty is if there are larger policy changes in September, as we move into the time of year when respiratory viruses tend to transmit slightly better, what will happen then? And that remains very unclear.”

Prof Keeling told the committee ministers were given information leading up to lockdown about what would happen if the epidemic was just allowed to run.

“In the early stages, in the absence of a lockdown, the very alarmist values that were coming out were really about a worst-case scenario,” he said.

“So if we just let the epidemic run, how bad could it be? And that’s the sort of information policy-makers needed at that time.

“If the lockdown had been very strict, if we’d have thought more about what was happening in care homes and hospitals, as you’ve heard, early on maybe that was one of the areas where modellers did drop the ball.

“With hindsight, it’s very easy to say we know care homes and hospitals are these huge collections of very vulnerable individuals, so maybe with hindsight we could have modelled those early on and thought about the impacts there.”

But he added: “Considering the amount of information we had at the time, I think the models offer our best estimates of what could happen in the short-term.

“Long-term predictions are much, much more difficult.”

Asked about the approach in Sweden, which rejected a lockdown, Prof Ferguson said he had the “greatest respect for scientists there” who “came to a different policy conclusion but based really on quite similar science”.

He added: “They make the argument that countries will find it very hard to really stop second waves… I don’t agree with it but scientifically they are not that far from scientists in any country in the world.”

Prof Ferguson said Sweden was not, however, now seeing a decline in death rates most European countries are seeing.

“But nevertheless it is interesting that adopting a policy which is short of a full lockdown… they’ve gone quite a long way to (achieving) the same effect.”

Dr Adam Kucharski, of the London School of Hygiene and Tropical Medicine, told the committee that “speed is really of the essence” with regards to the test and trace strategy.

“The nature of the evidence we have on transmission is that by the time someone shows symptoms, they have probably been infectious for a day or two already,” he said.

“So that means by the time someone has symptoms, reports as a case, their contacts have potentially already been infected, and those people may themselves become infectious three or four further down, so really very soon after.

“So I think that what that shows is that for these test and trace, these targeted measures to work, speed is really of the essence.”