Keir Starmer is now self-isolating as one of his child have tested positive for Coronavirus.
The Labour leader had just finished PMQs when he was notified that he will need to isolate for the fourth time.
Mr Starmer had been taking tests ever day and even tested negative on Wednesday morning.
He said: "I know it's my responsibility to follow the rules – my family and I are now self-isolating."
This leaves the Prime Minister, the Chancellor, the Health Secretary and the Leader of the Opposition working remotely.
The Labour leader will undergo the isolation process with his family.
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Keir Starmer had been grilling Boris Johnson on his bid to avoid self-isolation earlier this week during PMQs
News of his self-isolation came hours after Mr Starmer had grilled the Prime Minister on his bid to avoid self-isolating earlier this week.
The Labour leader told the Commons: "Can I wish the Prime Minister, the Chequers one, well in his isolation.
"With half a million people self-isolating, I think we were all a bit surprised that the Prime Minister, the Chancellor and the Cabinet Office minister were all randomly chosen for a get-out-of-isolation-free card.
Now Keir Starmer and the Prime Minister Boris Johnson are currently self-isolating
“But it’s good that the Prime Minister finally recused himself, even if it took a public outcry, for the Communities Secretary to be humiliated on live TV and a trip to a country estate."
Mr Johnson and Chancellor Rishi Sunak had been in contact with Health Secretary Sajid Javid who tested positive for Covid on Saturday.
Initially Mr Johnson and Mr Sunak said they had been invited to join a daily worplace testing programme which meant they would not need to isolate.
But they were forced to back down on the plans and enter isolation amid widespread public anger that they would be free while tens of thousands of people are forced to miss work or school over coronavirus contacts.
As schools approach their summer holidays, figures released by the Department for Education (DfE) showed another huge drop in attendance with approximately one in seven pupils not in school (1.05 million).