I notice today the experts are saying 17% of people in London have had the Virus - quite a jump from 10% a few days ago - this time they think the figures are more accurate, but could be 4 weeks out of date, so it will be higher by now.

The rest of the country is officially 5% but will catch up to the London figure with time, so in say 2 weeks time will be 17% too.

I have been posting for over a month that the 4% figure infection rate was wrong, based on number of UK CV19 deaths and quoted fatality rate, say approx. 50,000 deaths (remember some CV deaths are not officially recorded) multiplied by 250 fatality rate (0.004) = 12.5m infections = 19% of the UK population.

So here's today's maths lesson:

Firstly, the population of London is approx. 9.3m with the population of the rest of England (as these estimates relate to England not the UK) being approx. 45.7m. If 17% of people in London and 5% elsewhere in England have already had the disease, that equates to a total of approx. 3.9m people in the whole of England.

There are 55m people who live in England. For 17% of that population to have been infected would mean a total of 9.4m people. Subtracting the 3.9m who are estimated to have already been infected gives us a balance of 5.5m people.

The current infection rate (according to ONS analysis) is 0.25% of the population, which equates to 137,000 in England. To reach your statement that 17% of all people in England will have had the disease in 2 weeks' time, would require those 137,000 to infect (directly or indirectly) 5.5m people within a fortnight.

If we are generous and assume that the infectious period for Covid-19 is just 7 days (the shorter the infectious period the lower the R number), then the R number would be the square root of 5.5m/137k which equals 6.3.

I don't think anyone has ever suggested it being as high as that and, if it was, a far higher number of the population than 3.9m would have already had the virus. I'm afraid I'm going to file this alongside the claim that "we'll all have had it by the end of May" that I read on here a couple of weeks ago.