Three Cabinet ministers were self-isolating on Thursday after the Australian deputy prime minister, who they met earlier this week, tested positive for Covid-19.

Dominic Raab, the Deputy Prime Minister, Michael Gove, the Communities Secretary, and Grant Shapps, the Transport Secretary, were the three ministers.

They all met Barnaby Joyce while he was visiting the UK. Mr Joyce tested positive after flying to the US.

If Mr Joyce is found to have caught the omicron variant of Covid then, under the current rules, all three of the politicians may have to self-isolate for 10 days.

Current rules in England state that if someone is deemed to have come into contact with a person who has omicron, there is a 10-day mandatory isolation which cannot be broken by a negative Covid test result.

The rules are changing, however, with Boris Johnson announcing as part of his Plan B measures that daily negative test results will be allowed to break the self-isolation rule.

However, it remains unclear when the rule change will come into force. Downing Street sources indicated it will happen before Christmas, but no date has been announced.