A new variant of Covid-19 has been detected in Yorkshire where residents are being told “please don’t be alarmed”.

Public Health England (PHE) has identified a new strain of the virus and it is being described as a variant under investigation.

The Prime Minister’s official spokesman said: “There have been a number of variants throughout the pandemic and there will continue to be so.

“There are three mutations of the B1617 (Indian) strain, as I think has been discussed previously, but as we do with all variants where we spot and identify them through our genomic sequencing programme, we will continue to monitor them and we will designate them as variants under investigation, and then variants of concern if we deem them to be of greater risk.

“But again, as you’ve seen throughout the pandemic, that’s what we’ve done and we won’t hesitate to put in measures that we think are necessary to try and tackle the transmission of any variants.”

Asked whether the discovery of the new variant would have an impact on the next stage of restrictions lifting on June 21, the spokesman said the five-week gap between measures relaxing would allow the variant to be monitored.

He added: “As the Prime Minister has said, we will continue to look at all the statistical evidence and data, and we’ll set out our plans as soon as the data allows.”

Greg Fell, director of public health in Sheffield, said his team had been monitoring the new strain – referred to as VUI-21MAY-01 or AV.1 – after Public Health England (PHE) announced 49 cases were identified, mostly in Yorkshire and the Humber region.

But Mr Fell stressed there is no evidence to suggest this strain is any more transmissible than other variants or that the vaccines do not work against it.

Mr Fell said in his statement: “We have been monitoring VUI-21MAY-01 and we’re managing this carefully as we do with all outbreaks across the city.

“There is no evidence to suggest this strain is any more transmissible than other strains identified in the UK and across the world, or to suggest the vaccine doesn’t work against this strain.

“Please don’t be alarmed, we want you to continue doing what you have been for the past year. Follow the guidance, continue to wash your hands regularly and wear a mask indoors.”

The statement added: “We work very closely with NHS Test and Trace and Public Health England on these matters to make sure all appropriate public health interventions are being carried out, including any additional contact tracing and targeted testing.

“Where cases have been identified, additional follow-up of cases, testing of contacts and targeted case finding will be used to limit the spread of variants.

“If you have symptoms of Covid-19 you should seek to have a PCR test as soon as possible. If you are tested positive then you and your household must stay at home and not leave the house for any reason for 10 days.”