Sir Keir Starmer has been forced into self-isolation after one of his children tested positive for coronavirus this lunchtime.
The news comes two hours after the Labour leader attended the Commons to participate in PMQs – which Prime Minister Boris Johnson contributed to virtually from his own period of self-isolation at Chequers.
It is believed Mr Starmer discovered the test result after his appearance at PMQs.
He will now begin the quarantine process alongside his family.
A spokesperson for the Labour leader said: "One of Keir's children tested positive for COVID this lunchtime.
"In line with the rules, Keir and his family will now be self-isolating.
"Keir was already doing daily tests and tested negative this morning. He will continue to take daily tests."
The Labour Party has confirmed this is the fourth time their leader has had to isolate since the pandemic began.