In line with government advice, the 58-year-old must stay at his north-London home for 14 days since Tuesday – when he was last in contact with the infected person.
He is ‘well and not showing any symptoms’ and will be out of self-isolation by December 16.
Labour leader Keir Starmer, 58, has been forced to self-isolate and work from home until mid-December after a member of his private office tested positive for coronavirus
A spokesperson for the politician said: ‘This afternoon Keir Starmer was advised to self isolate after a member of his private office staff tested positive for the coronavirus.
‘Keir is well and not showing any symptoms. He will now be working from home.’
This is the second time that he has been required to self-isolate.
In September Sir Keir went into quarantine when one of his children developed possible symptoms of the disease only for a test to come back negative two days later.
It is understood that several people in Sir Keir’s team are having to self-isolate, although a rota system is operated in his office to ensure that contacts are limited.
A source said it was an ‘irritant’ but they were ‘used to it’. Sir Keir had to isolate in September when a member of his own household needed a test.
Sir Keir visited the Portsmouth Gin Distillery in Southsea two days ago, on Thursday, seeing gin production and also how the company has been producing hand sanitiser during the pandemic.
A decision has yet to be taken on whether Sir Keir will participate in Commons proceedings next week virtually, or hand duties to deputy leader Angela Rayner.
Sir Keir pictured arriving for a visit to Portsmouth Gin Distillery in Southsea, Portsmouth, on Thursday. He saw gin production and also how the company has been producing hand sanitiser during the Covid-19 pandemic
The Labour Party leader during a visit to the Portsmouth Gin Distillery in Southsea on Thursday. It is understood that several people in Sir Keir’s team are having to self-isolate
There are crucial debates and votes on the internal Market Bill as well as PMQs. It is thought that he would prefer to take PMQ’s virtually.
‘We will ask the Speaker to see what we can do,’ a source said. ‘Then we will decide.’
Ms Rayner deputised for Sir Keir when he had to self-isolate in September, but Boris Johnson recently took the session by video link when he was forced to quarantine.
It follows the Prime Minister also self-isolating recently alongside six other Tory MPs, following a Downing Street meeting on November 12.
Mr Johnson was told to self-isolate by NHS Test and Trace after Lee Anderson, the MP for Ashfield, tested positive for coronavirus.
At the time, Sir Keir said Mr Johnson was right to self-isolate, adding: ‘It is important for all of us to say that we have got to comply with the advice and guidance.’