THE concerning Indian Covid-19 mutation could “scupper” the UK’s march to freedom, a leading scientist has warned, despite the lockdown and vaccine programme leading to cases falling to a seven-month low.

Covid-19 infections across the UK dropped to the lowest level since the autumn, according to the latest figures, however Bradford has the highest rate in the country.

But a professor of immunology has called for Britain to be on its guard against a fourth wave after 77 cases of another possible vaccine-busting mutation was recorded domestically.

Public Health England (PHE) reported that 73 cases of the B.1.617 variant, which was first discovered in India, had been found, while a further four cases were identified in Scotland.

There are fears the variant - which has come from India which is currently in the midst of a deadly second wave of Covid-19 - could be resistant to vaccines, and there have been repeated calls recently for the Southeast Asian nation of more than a billion people to be added to the UK's red travel list.

Imperial College’s Danny Altmann said that as a result, those arriving into the country from India should be subject to a hotel quarantine if the UK is to shut out variants that could set back the Prime Minister’s lockdown easing plans.

But despite the warnings, Downing Street has insisted Boris Johnson’s trip to India later this month – his first major international visit since securing a Brexit trade deal with Brussels – will go ahead.

The decline in infection levels across the UK marked a contrast to rising case rates in other parts of the world.

World Health Organisation (WHO) director-general Tedros Adhanom Ghebreyesus said coronavirus rates globally were “worrying”, as India recorded more than 217,000 daily cases on Friday, pushing its total since the pandemic began past 14.2 million.

Prof Altmann said the discovery of the Indian variant in the UK should warrant India being placed on the UK’s “red list”.

Officials have designated its version a variant under investigation (VUI) rather than a variant of concern (VOC), such as the Manaus (Brazil) or South African variants.

But Prof Altmann said he suspected the Indian mutation would be escalated to a variant of concern as it holds properties that allow it to evade the coronavirus vaccines currently on offer, like the South African variant, and was more transmissible, in a similar fashion to the Californian version of Covid.

“I think we should be terribly concerned about it,” he said.

“They (variants of concern) are things that can most scupper our escape plan at the moment and give us a third wave. They are a worry.”

Prof Altmann said he found it “mystifying” and “slightly confounding” that those flying in from India were not required to stay in a hotel.

The country is not currently on the Government’s “red list” for travel, which sees people who have been in those countries in the previous 10 days refused entry to the UK.

British or Irish nationals, or people with UK residency rights, are able to return from red list countries but must isolate in a quarantine hotel for 10 days.

No 10 said Mr Johnson’s visit to India “is still happening later this month” but, as already announced this week, would be “slightly shorter” than the initial four-day planned trip, with most of the meetings expected to be shoehorned into a single day.

A Downing Street spokesperson said the Government’s red list of travel ban countries is “under constant review”, when asked why India did not feature on it.