As well as the 480,000 courses of Lagevrio, the UK has ordered 250,000 courses of Ritonavir, a drug produced by Pfizer that is usually used to treat HIV/Aids. However, ritonavir has yet to receive MHRA approval.

Lagevrio, produced by Ridgeback Biotherapeutics and Merck Sharp & Dohme, works by preventing the Covid virus from multiplying, keeping levels low in the body and reducing the severity of the disease. The MHRA said the drug should be taken as soon as possible following a positive Covid test and within the first five days of symptoms.

Patients who will be eligible for it under the MHRA’s ruling will have at least one risk factor for developing severe Covid including obesity, diabetes, heart disease or being over 60.

An outline of the study issued by the Antivirals Taskforce in the summer said it would examine the impact of treatments on clinically vulnerable patients who test positive for Covid, as well as some non-vulnerable household contacts of those who test positive. It is not clear whether non-vulnerable people will still be included in the pilot.

The Government appears to have downgraded the original ambition of the UK Antivirals Taskforce, set up by Mr Javid’s predecessor, Matt Hancock, in April, from potentially offering treatments to all Covid patients to instead getting drugs to those deemed clinically vulnerable, including people with pre-existing medical conditions who cannot have a vaccine.

As the omicron variant continued to spread in the UK, government advisers suggested an extension of the current requirement to wear masks in shops and on public transport until the new year may now be inevitable.

“I suspect it may be [extended],” said one member of the Sage committee of scientific advisers. “We do know that those restrictions work, and they can be used in a mass setting.”

Several Cabinet ministers said they considered the current restrictions “proportionate” while ministers await the first data on the link between omicron, hospitalisations and deaths.

One senior minister warned that while they “can cope” with the mask-wearing requirement being extended beyond the initial three-week review mark later this month, continuing the new self-isolation requirement for vaccinated contacts of people with omicron would meet “some pushback” in the absence of data justifying the decision.