The news was announced by a Labour Party spokesperson, shortly before Starmer was to attend Prime Ministers’ Questions in the House of Commons and ahead of Chancellor Rishi Sunak’s budget speech. Earlier, Starmer posted a photo on Twitter showing him and some party colleagues preparing for the day’s budget revelations.

Despite being double-jabbed against the virus, Starmer will have to quarantine for 10 days. It might mean that he will miss the beginning of the UN Climate summit (COP26), though it is unclear if he plans to attend it.

Though the positive test result was a first for Starmer, he is no novice at pandemic-related self-isolation: he had already quarantined four times previously, due to having been a close contact of Covid-positive colleagues and relatives.

England’s Covid restrictions and rules have since changed, meaning that fully vaccinated close contacts of Starmer do not have to automatically self-isolate. Shadow Chancellor Rachel Reeves and Shadow Chief Secretary to the Treasury Bridget Phillipson who had been photographed with Starmer earlier today, both tested negative, Labour sources told the Guardian.

Just a day earlier, Covid guidance for Parliament was updated to say that all staff, visitors, contractors and press must wear masks to combat the spread of Covid. However, MPs remain exempt from this order.