Half of Sweden's population could be infected with coronavirus by the end of the month, a statistician has warned.

Tom Britton, a mathematics professor from Stockholm University, said it is possible that up to a million people are already infected with the virus - though the country has only confirmed 5,466 cases.

Using mathematical models he believes the number of new daily infections will peak around the middle of the month, with up to 5million people infected by April 30.

Sweden has so-far resisted calls to go on lockdown like other European countries and has instead asked people to act 'like adults' by taking sensible precautions.

A million people in Sweden could already be infected with coronavirus and half the country's 10million population could have it by the end of the month, one mathematician has predicted

The country has officially confirmed just 5,466 cases - but scientists have warned the government that not enough testing is being carried out

Mr Britton told Radio Sweden that it is too early to tell what effect, if any, these measures have had on the spread of the virus - because the only reliable data he has are death figures.

Using death figures he is able to calculate an estimated number of infections, but it means looking around three weeks into the past - since this is roughly how long it takes a person to get sick enough to die from coronavirus.

Since Sweden's social distancing measures were only first introduced two weeks ago, it means they will not yet show in that data.

Using statistical modelling, Mr Britton explained that he can work forwards from the number of infections three weeks ago to estimate how many are infected now.

Professor Tom Britton predicts that the peak of Sweden's infection curve will fall around April 15, with pressure peaking in hospitals two weeks later

The calculations are based on a number known as 'R' - which stands for the number of people the average person with the virus infects before they stop being infectious.

With no social distancing, that number is thought to be around 2.5, with social distancing it falls significantly. Anything under 1 means the virus starts to die out.

Based on his calculations, Mr Britton believes peak day for infections will fall around April 15 with up to half of Sweden's 10million population infected by April 30.

Pressure on hospitals will then peak around two weeks after April 15 as those who fell sick on that date develop symptoms, with some requiring intensive care.

'China succeeded in [reducing its R value] by very comprehensive measures, and very quickly, so that less than 1 per cent will be infected in Wuhan,' he said.

'I am not convinced that we will be as effective in Sweden.'

Mr Britton said he is in touch with a group of mathematicians advising the government, which includes a former student of his, but is not directly involved in government efforts to curb the virus.

Sweden's leaders have urged calm, insisting that sensible social distancing measures and increasing intensive care capacity will see them through the crisis.

Sweden has so far resisted calls to lock the country down like most other European nations, and instead advised people to 'act like adults' and socially distance themselves

But others have insisted the government must act faster and go further to prevent scenes from Italy and Spain - where tens of thousands have died - being repeated.

Last week, a petition signed by 2,000 doctors, scientists, and professors was delivered to the government asking for more stringent measures to be put in place.

Among the signatories was Professor Carl-Henrik Heldin, chairman of the Nobel Foundation.

Meanwhile Cecilia Söderberg-Nauclér, a virus researcher from Sweden's Karolinska Institute, echoed their fears.

Speaking to The Guardian, she said: 'We’re not testing enough, we’re not tracking, we’re not isolating enough – we have let the virus loose.

'They are leading us to catastrophe.'

The WHO's Europe branch said there were 464,859 confirmed cases of COVID-19 and 30,098 deaths in the 53 countries that make up its region.

Some 80 per cent of those who died from the virus had at least one underlying illness, in particular cardiovascular disease and diabetes.