A new variant of the coronavirus has been dubbed Delta+Delta by some. UK experts say it may spread more easily than the regular Delta variant.

The UK Health Safety Agency (UKHSA) has raised the mutated virus to the "variant under investigation" category to reflect the potential risk.

There is currently no evidence that the new variant causes more severe disease.

Meanwhile, existing vaccines should still protect the population, scientists are confident.

The majority of coronavirus infections in the UK are of the regular Delta variant, but cases of the 'Delta+' or 'AY.4.2' variant have been increasing.

***The latest official figures show that 6% of Covid-19 cases fall into this category.

Experts say it is unlikely to spark a large outbreak or render existing vaccines ineffective. But officials point to some early evidence that it may have a higher rate of new infections in the UK than the Delta variant.

The UK Health Safety Agency said: "***This sub-strain has become more common in the UK in recent months and there is some early evidence that it may have a higher rate of new infections in the UK than the Delta variant. "

Unlike Delta, however, it has not yet been identified as a "variant of concern" -- a distinct variant of the virus that is defined by risk level.

There are thousands of different types of coronaviruses and their variants circulating around the world. Viruses mutate all the time, so it's not surprising to find new types of variants appear.

The AY.4.2 variant is an offshoot of the Delta variant and includes some mutations affecting the spike protein that viruses use to invade our cells.

Related variants, Y145H and A222V, have been found in other coronavirus sub-lines since the beginning of the global pandemic.