Boris Johnson’s defence on Covid risk to care homes hit by new revelation

Prime minister had broached issue of asymptomatic transmission publicly with advisers long before testing rules were introduced

Boris Johnson's claim that a lack of knowledge about the asymptomatic transmission of Covid-19 put care homes at risk has been further undermined after it emerged he openly discussed the potential scale of symptom-free transmission.

The prime minister has already been accused of misleading parliament over the claim. He made it last week after the high court ruled that the government had acted unlawfully in ordering the discharge of patients to care homes without testing in the spring of 2020. Johnson told the House of Commons: What we didn't know in particular was that Covid could be transmitted asymptomatically."