Sign up for the latest from M.E.N. political editor Jennifer WilliamsBoris Johnson will hold a Downing Street press conference on the government's response to the coronavirus pandemic this afternoon.The prime minister will be joined by England’s chief medical officer Professor Chris Whitty and the government's chief scientific adviser Sir Patrick Vallance.It comes after Mr Johnson previously said he was 'very concerned' about a new variant of the virus identified in Brazil.Scientists are studying the new strain to find out whether it poses more risk than previous strains.The discovery led the government to impose an urgent travel ban on 16 countries including Brazil and Portugal, but oppositions MPs have criticised ministers for not acting.