CNBC reports that Boris Johnson is expected to announce a delay to the next phase of England’s reopening of up to four weeks on Monday, amid a surge in the delta variant of Covid-19.

Rules including the use of face masks, limiting the number of people who can meeting indoors and out, and shutting nightclubs and similar venues were due to be lifted on June 21, but British media reports suggest this could now be pushed back as late as July 19. At the moment, gatherings are limited to six people indoors and 30 outdoors.

People will also be advised to continue working from home where possible, according to reports.

New figures from Public Health England indicate that 42,323 cases of the delta variant of the coronavirus have now been confirmed across the U.K., an increase of 240% from last week, while the country’s transmission rate is at its highest since January.