Boris Johnson is still displaying coronavirus symptoms, meaning he may not be able to leave No 11 Downing Street on Friday, where he is self-isolating. The prime minister’s official spokesman said Johnson was still symptomatic, six days after he first came down with signs of the illness. If he still has a temperature on Friday, he will not be able to leave quarantine as planned, despite having observed a recommended seven days in isolation. The spokesman said: “What the guidelines say is that if you still have a high temperature, for example, you should keep self-isolating until your temperature returns to normal. The guidance is that you should stay at home for seven days or for longer if a high temperature persists.” When asked if the prime minister had a temperature, the spokesman said only that he continued to have “mild symptoms”. Johnson has been leading the response to coronavirus from No 11 by video conference with other key ministers and officials for almost a week. His chief medical officer, Chris Whitty, also continues to work from self-isolation and did not provide an update on his condition. However, Matt Hancock, the health secretary, will leave self-isolation on Thursday after seven days of being in quarantine. He is expected to give a press conference in No 10 setting out a new “action plan” for testing for coronavirus, after a backlash against the government’s poor testing numbers. A No 10 spokesman said the government “acknowledges that more needs to be done and we need to make progress quickly” in relation to testing NHS staff, with 2,800 undergoing tests so far out of 500,000 frontline workers. Downing Street also confirmed the government was looking at the idea of “immunity passports” to allow some people who have had coronavirus to leave the lockdown. The spokesman said: “That’s something other countries have done. We are always watching what other countries are doing and looking to learn.”