Travel by visitors to the UK from South Africa has been banned amid concern over a variant of Covid-19 linked to the country.

People who have been in or transited through South Africa in the last 10 days are no longer allowed into the UK.

The new rule does not apply to British and Irish nationals - but they will have to self-isolate.

Covid-19: UK bans travel from South Africa over variant https://t.co/flLkWAbkFn

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The variant was found in London and north-west England, both in contacts of people who had been in South Africa.

The Department for Transport said the ban reflects the "increased risk" from the new variant, but will be kept under review.

Anyone required to quarantine will need to do so for 10 days, along with members of their household.

UK visa holders and permanent residents arriving from South Africa will not be affected - but they will also need to self-isolate.

The government had already ordered anyone in the UK who has travelled to South Africa in the past fortnight, and anyone they have been in contact with, to quarantine immediately, along with their households.

The travel ban came into effect at 09:00 GMT on Christmas Eve, after the government announced six million more people in England were being moved into the highest tier four restrictions on 26 December.

At a Downing Street press briefing on Wednesday, Health Secretary Hancock said the new variant linked to South Africa was "highly concerning".

Any exemptions to quarantine usually in place - including for those related to employment - do not apply, he added.

The variant was detected for the first time in the UK on Tuesday.

Scientists in South Africa say it is still being analysed, but the data are consistent with it spreading more quickly.

It shares some similarities with another new Covid variant that has already been detected in the UK, although they have evolved separately.

Both have a mutation - called N501Y - which is in a crucial part of the virus that it uses to infect the body's cells.