COVID-19: Two cases of Omicron variant detected in UK - with targeted testing to be rolled out in affected areas

Two cases of the Omicron coronavirus variant have been detected in the UK, the health secretary has said.

Sajid Javid also said there would be targeted testing in the areas where the cases were found - in Brentwood, Essex, and in Nottingham.

It had previously been reported that one of the cases was in Chelmsford, but that has since been corrected.

Mr Javid said the two individuals are now self-isolating along with their households, while further tests are carried out.

The two cases are "linked", the health secretary added, and that connection has been traced to South Africa.

In addition, four more countries are being added to the travel 'red list' from 4am on Sunday: Angola, Mozambique, Malawi and Zambia.

Mr Javid said he only found out about the Omicron cases "late last night" when he was contacted by the UK Health Security Agency.

In a warning that fresh measures may be on the way, he said: "We've been always very clear that we won't hesitate to take further action if that is what is required.

"If anyone has travelled to any of these four countries, or any of the other recently red-listed countries in the last 10 days, then they must self-isolate and take PCR tests."

Boris Johnson is due to take part in a news conference at 5pm with the UK's chief medical adviser Professor Chris Whitty and chief scientific adviser Sir Patrick Vallance "to set out further measures".

Making the announcement, Mr Javid added: "This is a real reminder that this pandemic is far from over. If there is one thing that everyone can be doing, right now, is if they are eligible, please take your vaccine, whether it's your first shot, second shot, or your booster jab."

Omicron was on Friday declared by the World Health Organisation as a variant of concern, putting it in the same category as the Delta variant, which has caused waves of infection to sweep across the globe and forcing several European countries to re-enter lockdown.

The new variant is considered potentially more dangerous because it has around twice as many mutations as Delta, but experts say how much of a concern is still under investigation.

As well as southern Africa, Omicron, also called B.1.1.529, has also been detected in Belgium, Israel and Hong Kong, and possibly in Germany and the Czech Republic.

Professor Deenan Pillay, director of the Wellcome Trust-funded Africa Centre for Health and Population Studies in South Africa and professor of virology at UCL, told Sky News that he "strongly suspects" there will be more UK Omicron cases than the two detected so far.

He called for 'plan B' - mandatory face masks and work from home where possible - to be put in place in order to tackle it, but also stressed the need for vaccination because "colleagues in South Africa are reporting that of those individuals with this virus going into hospital... all of them are either unvaccinated or only partially vaccinated".

Governments around the world have suspended flights to and from countries in southern Africa as a result of the detection of the variant.

It will increase concerns that further measures could be put in place as Christmas approaches.

Mr Javid said: "We've always been really clear that we will do whatever is necessary to protect the progress that we have made as a country. We've come a long way, especially since the summer, and we keep all of this under review. If we need to take further action we will.

"Everything we know about this variant, our international partners know. We have been very open, and that is the right way of course, to help people know why we are concerned."

Before the addition of the extra four countries, six African countries - South Africa, Botswana, Lesotho, Eswatini, Zimbabwe and Namibia - were already on the red list, meaning British and Irish residents who arrive in the country from them nations must quarantine in a government-approved hotel for 10 days.

South Africa said on Saturday it was being punished for its advanced ability to detect new COVID-19 variants early, as AP reported that scientists there are scrambling to combat its lightning spread across the country.