British Prime Minister Boris Johnson announced Monday that the lifting of coronavirus-related restrictions in England would be postponed by four weeks. 

The restrictions that were originally meant to be removed on June 21 will now be lifted July 19 due to a high number of infections with the delta mutant, which first appeared in India. 

"We are very concerned about the delta mutation, which is spreading more quickly than what was stipulated in the roadmap in February," Johnson said.

Johnson stressed that he made the "difficult decision because we cannot continue (...) while there is a real possibility that the virus will outpace vaccines and result in thousands of additional deaths."

The goal is now to provide one dose for all adults and two doses for two-thirds of adults by July 19.

So far, about 80 percent of adults in the UK have received a single dose of the vaccine, while 57 percent have received both doses.