Fears are growing that the Indian variant of covid-19 could delay the UK's journey out of lockdown.
Experts say that vaccines have saved 12,000 lives across the country, but cases are surging in several places across the country, including Bolton and Sefton.
Scientists and government figures are holding urgent talks amid fears it could delay the end of lockdown rules - reports Mirror Online.
Boris Johnson said he was "anxious" about the B1.617.2 strain, which almost tripled in a week to 520 UK cases as of May 5.
But there is good news and bad news - and it's important to be aware of the facts.
So how did we get here - and why are authorities so worried?
Here are all your key questions answered.
1. Why are we concerned about the Indian variant?
Public Health England believes the variant spreads at least as well as the Kent variant still dominant in the UK.
Analysis is ongoing but if it turns out to have higher transmissibility then that would give it competitive advantage and it could start to take over.
2. How has this happened?
The original India variant - officially known as B.1.617 - was first detected in October and cases have been imported from abroad.
It is now known to be spreading in clusters in some communities.
3. Is there more than one Indian variant?
It has been re-characterised as three different subtypes, all with slightly different genetic mutations.
The UK has seen a sharp increase in one subtype known as B.1.617.2 which now makes up the majority of our cases and appears to be growing faster than others.
4. Why does it spread easier than previous variants?
It contains two key mutations to the outer “spike” protein of the virus that attaches to human cells.
Some experts believe it may be overpowering prior immunity from natural infections in some people who had caught earlier variants.
5. But the good news is...
There is no indication yet that it evades the protection offered by current vaccines.
This means even if it becomes more prevalent across the UK it should not make most people seriously ill.
Widespread vaccinations and natural immunity mean it should not trigger death spikes seen during earlier waves and put hospitals under pressure again.
6. Why does it put the June 21 reopening at risk?
Increasing Covid-19 rates with any variant would still kill some unvaccinated people - take-up is lower in ethnic minority communities - or those for whom immune protection has waned.
Higher viral prevalence also increases the chances that the virus will mutate again to stop vaccines working as well.
7. What can the UK do about it?
Make use of our world leading genetic sequencing to detect clusters and deploy surge testing.
The fact that we are hearing about this increase actually shows the system at work.
India is now on the travel Red List and restrictions must continue with countries where the variant is prevalent.
We are now reliant on our contact tracing systems to stamp out outbreaks.
Test and trace has under performed in Britain but is improving as more work is done by trusted local council teams.
