The world's most transmissible Covid-19 strain has infected the UK with six cases reported and worrying research it may be more infectious than the Delta variant.

The Lambda strain has puzzled World Health Organisation scientists after it spread to nearly 30 countries in the last four weeks. The mutation was originally discovered in Peru and is related to 81 per cent of the country's cases since April.

Peru currently has the highest mortality rate of anywhere in the world.

It is a worrying sign for the UK which has recently relaxed Covid-19 restrictions after 37 million people received at least one dose of a vaccine.

The country had returned to normality in recent weeks with pubs flooded by revellers enjoying their country's recent success at Euro 2020.

However, these civil liberties could change if the highly transmissible Lambda strain spreads across the community.

Medical staff transport a Covid-19 patient at the Honorio Delgado Hospital in Arequipa, Peru. The nation currently has the highest mortality rate of anywhere in the world. (Photo / AP)

Cayetano Heredia University Professor Pablo Tsukayama said the strand has exploded in Peru with the new variant currently making up 82 per cent of cases in the South American country.

"That would suggest its rate of transmission is higher than any other variant."

His claims were backed up by a report from London's Covid-19 Genomics Initiative at the Welcome Sanger Institute director Jeff Barrett.

"Lambda has a unique pattern of seven mutations in the spike protein that the virus uses to infect human cells. Researchers are particularly intrigued by one mutation called L452Q, which is similar to the L452R mutation to contribute to the high infectiousness of the Delta variant," he told the Financial Times.

There is also concerning research that current vaccines are not as effective in neutralising the new strand, according to a report from scientists at the University of Chile, Santiago.

"Our data show for the first time that mutations present in the spike protein of the Lambda variant confer escape to neutralising antibodies and increased infectivity," they wrote in a pre paper report published last week.

- by Mitchell Van Homrigh, news.com.au