The UK has increased its Covid alert status from level three to level four, following a sharp and rapid increase in the number of Omicron cases.

The decision comes as the UK’s four chief medical officers and NHS England’s national medical director recommended to ministers that the level be raised.

It comes on the same day the UK Health Security Agency (UKHSA) confirmed that 1,239 cases of the new variant have been recorded in the UK.

Scottish deputy First Minister, John Swinney, has also said that the new strain had risen from 2 per cent of cases to 18 per cent in a week, doubling every two days, compared to every two weeks for past variants.

Now, Boris Johnson is preparing to address the nation at 8pm with a recorded statement about the booster vaccine programme, but there have been no talks of new restrictions yet.

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According to Government guidance, the UK’s level four Covid alert means that the epidemic is 'in general circulation, transmission is high and direct Covid-19 pressure on healthcare services is widespread and substantial or rising'.

In a joint statement, the CMOs and NHS England’s Professor Stephen Powis said the emergence of Omicron “adds additional and rapidly increasing risk to the public and healthcare services”.

They added: “Early evidence shows that Omicron is spreading much faster than Delta and that vaccine protection against symptomatic disease from Omicron is reduced.

“Data on severity will become clearer over the coming weeks but hospitalisations from Omicron are already occurring and these are likely to increase rapidly.”

The five officials, including England’s CMO Professor Chris Whitty, Northern Ireland’s Sir Michael McBride, Scotland’s Professor Gregor Smith, and Wales’ Dr Frank Atherton, said the NHS was already under pressure “mainly driven by non-Covid pressures”, with Omicron’s ability to escape vaccines “likely” to add to those demands.

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“It is extremely important that if you are eligible, you get your Covid vaccination now – whether this be your first, second or booster dose,” they said.

“People should continue to take sensible precautions including ventilating rooms, using face coverings, testing regularly and isolating when symptomatic.”

Today, Scotland confirmed a further 4,002 new coronavirus cases in the last 24 hours.

Among those cases there were 38 new Omicron variants identified which takes the total to 159.