Boris Johnson and Sir Keir Starmer both held remote meetings of their top teams on Tuesday in the latest sign of rising concerns about the spread of Omicron.

The Cabinet held its first virtual meeting for months, with England’s chief medical officer Professor Chris Whitty issuing a stark warning to expect a “significant increase in hospitalisations” as cases of the coronavirus variant increase.

The Prime Minister told his team that a “huge spike” of Omicron was coming, Downing Street said.

The Prime Minister’s official spokesman said Cabinet took place virtually “in light of the increasing number of cases and our advice to work from home when possible”.

Meanwhile two members of the shadow cabinet announced they had tested positive for Covid-19 and were self-isolating.

Shadow chancellor Rachel Reeves said she had tested positive and was awaiting the result of a confirmatory PCR.

“I’m so grateful to have had the booster just three days ago,” she said.

“But this shows how much of a race against time it is to beat Omicron.

“Vaccines are our best weapon against Covid. Please get boosted as soon as you can to protect your friends, family and our NHS.”

Shadow environment secretary Jim McMahon said he was self-isolating following a positive PCR test.

Neither MP will be able to vote on the Government’s Plan B package of measures to limit the spread of Omicron – both said they would have supported it, in line with Labour’s policy.

Mr McMahon said he was “gutted” that he would now also miss his booster jab appointment, adding: “If you are able to have it, please do.”

Tuesday’s shadow Cabinet meeting took place on Zoom.