He also thinks that if we follow social distancing the increase in deaths will stop.
Professor James Naismith, director of the Rosalind Franklin Institute said: "It can take up to two weeks from infection to onset of symptoms. For over 80% of people these symptoms are mild, for the much smaller number who develop the most serious illness, intensive care is needed around 10 days later.
"For those who do not recover but die, data from China suggests this takes around another four days. The tragic deaths today will be from people infected roughly a month ago. It is inevitable that there will be more tragedies for families ahead.
"We can reduce the final death toll only by following current Government advice. We must expect and welcome changes in Government advice as science, medicine and social science work together to learn more."
Prof Naismnith spoke after a further 209 people in the UK died after being tested for Covid-19, bringing the total to 1,228, and described it as "a terrible loss."
He added: "It is true that this is less than might have been expected from exponential growth. However, daily numbers can be lower (or higher) than expected due to random factors.
"It is far too early to conclude that the lower number today than yesterday is not simply due to chance."
Other academics have cautioned people not to assume that because the 209 figure was lower than the 260 who died in the previous 24 hours, it meant the disease was under control.
Eleanor Riley, professor of immunology and infectious disease, University of Edinburgh, said: "It would be most unwise to infer any trend from a single day's data.
"Only when the epidemic has peaked - which is some time away - and we get sustained daily reductions in new cases and then sustained daily reductions in deaths, will we know that we are beginning to get on top of the epidemic."
Professor Sir David Spiegelhalter, chairman of the Winton Centre for Risk and Evidence Communication at the University of Cambridge, said: "It may seem callous to say that 209 deaths is reassuring, but it breaks the run of 30% daily increases we have seen recently.
"But it is still too early to claim that the curve is beginning to flatten off.
"It is also important not to over-interpret counts for single days: delays in reporting can lead to the numbers varying far more than one would expect by chance alone. For example, one of the deaths reported today actually occurred 13 days ago."