The government's chief scientific adviser has said models showing potential Covid-19 daily death figures are not intended to "scare people" but to give the public a "scenario" of what could happen if nothing is done to tackle the virus.
Sir Patrick Vallance was questioned by MPs at the Science and Technology Committee over a model he presented at the most recent government press conference, which showed there could be 4,000 coronavirus deaths a day by the peak of the second wave.
One MP suggested the model would have "frightened a lot of people around the country", to which Sir Patrick said that was not his intention.
"I positioned that, and if that didn't come across then I regret that, but I positioned that as a scenario from a couple of weeks ago, based on an assumption to try and get a new reasonable worst-case scenario."
Sir Patrick added that the 4,000 deaths figure was a model, not a forecast, but defended the figure against criticism that it was based on old data, saying "I don't think it is fair to say it is discredited".
England's chief medical officer Professor Chris Whitty accepted that death rates will probably be lower than 4,000 a day, but said reaching the peak of deaths in the first wave - 1,073 a day - is a "entirely realistic situation".
"You don't need too much modelling," he said, to see that demand for NHS beds is on an exponential upward curve."
He added: "People can take different projections if they wish. But getting to the stage we got to in April - and if we do nothing carrying on up from there - is entirely realistic."
Sir Patrick defended figures presented back in September predicting 50,000 cases a day and 200 deaths had not been there to "scare people" but to "give a scenario".
He defended the use of modelling at press conferences, saying they are "scenarios" rather than predictions and that previous scenarios had been right.
He told the Committee: "As it happens, the numbers turned out to be very close to that, by the time we got there.
"So it's very difficult to project forward in a way that doesn't inevitably lead to the problem of 'Is that real?'
"No, it's not real, it's a model, but it is what we need to understand because this is a disease which is spreading like all epidemics, in a way that will affect us in weeks to come but isn't felt today."
Prof Whitty said that although Tier 2 and Tier 3 restrictions in England were having an effect in reducing the R number - the reproduction rate of the virus - they had not been able to get it below 1, the point at which it is spreading.
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He said in areas such as Liverpool where hospitals were already under pressure, only a small increase in the R number could lead to "quite serious trouble".
While infection rates have fallen among younger people, who are less likely to become seriously ill with coronavirus, Professor Whitty said the same cannot be said for older people.
He told MPs: "The rates are still steadily tracking up in all the data that I have seen in the older age groups who are the ones who are likely to translate into hospitalisations, ICU cases and deaths."