London, Nov 15 : Another 26,860 people in Britain have tested positive for Covid-19, bringing the total number of coronavirus cases in the country to 13,44,356, according to official figures released on Saturday. The coronavirus-related deaths in Britain rose by 462 to 51,766, the data showed. Britain is the first European nation to record more than 50,000 coronavirus deaths. It is the fifth country in the world to hit the tragic milestone, following the US, Brazil, India and Mexico, the Xinhua news agency reported. Earlier Saturday, a British government scientific adviser warned that the next fortnight will be "absolutely crucial" to ensure an end to England's month-long lockdown on December 2 as planned, Professor Susan Michie, who is on the government's Scientific Advisory Group for Emergencies (SAGE), said the next two weeks will be "very challenging, partly because of the weather (and) partly because, I think, the promise of a vaccine may be making people feel complacent". Michie said: "The vaccine is very unlikely to come in until the end of the year or beginning of next year and that's going to make no difference to the current second wave." "So I think for the next two weeks, everybody has to really get all their resolve together," she added. According to SAGE, Britain's coronavirus reproduction number, also known as the R number, has dropped slightly to a maximum of 1.2. If the R number is above one, it means the number of cases will increase exponentially. England last week entered into a month-long national lockdown until Dec.2, the second of its kind since the coronavirus outbreak in Britain, in a bid to quell the resurgence of coronavirus. To bring life back to normal, countries such as Britain, China, Germany, Russia and the United States are racing against time to develop coronavirus vaccines. /IANS