UK Labour leader Sir Keir Starmer has tested positive for coronavirus and Angela Rayner will deputise for him at prime minister's questions, a party spokesman has said.
It comes as coronavirus testing rules are set to be eased in Britain to reduce the time people have to spend in isolation, as Boris Johnson acts to combat staff absences in key parts of the economy and health service.
People who test positive on a lateral flow test will no longer need a confirmatory PCR to begin the self-isolation period if they do not have symptoms, potentially allowing them to return to work earlier, under plans being considered by UK ministers.
The change could be announced on Wednesday as the prime minister argues to his cabinet they should stick by the Plan B measures in England – including work-from-home guidance, mask-wearing and Covid health passes – despite admitting parts of the health service will feel "temporarily overwhelmed".
He will face Ms Rayner at prime minister’s questions and then make a Commons statement where he will face possible challenges from Tory MPs critical of restrictions amid concerns over staffing shortages.
Under the changes to the testing regime, first reported by the Daily Telegraph, the PCR capacity in laboratories will be limited to those with Covid-19 symptoms.
Currently those without symptoms who test positive on a lateral flow are asked to order a PCR test and only begin their isolation period when they receive the second result, effectively forcing them to isolate for longer than seven days – particularly if there are delays in obtaining the confirmatory result.
A Government source said the change was being discussed but details were “still being finalised”.
Ministers are also expected to approve the scrapping of pre-departure tests for travellers heading to England, with transport secretary Grant Shapps keen to help protect the beleaguered aviation industry.
The Omicron-driven surge in coronavirus cases and the knock-on effect of staff absences is already causing major problems in parts of the health service.
A string of NHS trusts declared critical incidents and hospitals in Greater Manchester said they will pause some "non-urgent" surgery over the "rising impact" of Covid-19 and staffing shortages.
A record 218,724 lab-confirmed Covid-19 cases were announced in England and Scotland on Tuesday, though the figure will have been inflated by delayed reporting over the holiday period.
NHS England figures showed 15,044 patients with Covid-19 were in hospital on Tuesday morning, with 797 requiring mechanical ventilation.
Ahead of Wednesday’s Cabinet meeting, Mr Johnson pledged to “fortify” the NHS to withstand the pressures and protect supply chains. He said 100,000 “critical workers” including those in transport, policing and food distribution will get lateral flow tests on every working day starting on Monday.
First Minister Nicola Sturgeon will update the Scottish Parliament on the pandemic on Wednesday afternoon. – PA