A sandwich factory in Northampton which supplies to M&S has shut down after it was reported that 292 workers caught coronavirus.
The Greencore Factory in the East Midlands town has voluntarily closed. The site employs 2,100 people.
Staff – along with their households – will need to isolate for two weeks.
Last week, Public Health Northamptonshire confirmed it was assisting the factory with containing the outbreak.
The Department of Health said that local testing data and analysis from the Joint Biosecurity Centre had shown a spike in cases in the area to be almost solely down to the outbreak at the Northampton factory, The Mirror reports.
“The factory will close voluntarily from today and employees and their direct households will be required to isolate at home for two weeks.
“The Health Secretary will introduce regulations to ensure that this self-isolation period is legally enforced. Anyone who leaves isolation prior to the two-week period ending without reasonable excuse will be subject to fines,” the department said.
The outbreak saw Northampton upgraded to an “area of intervention'” due to the spike in infections.
While Birmingham has a coronavirus infection rate of 29.1 per 100,000 people, Northampton’s rate is far higher at 78.4 as it is a much smaller place.
In all intervention areas bar Northampton, possibly because the outbreak is so localised, restrictions have been imposed, while enhanced support zone councils have received more backing and mobile testing units have been dispatched.
The Department of Health said Health Secretary Matt Hancock would bring in regulations “to ensure that this self-isolation period is legally enforced” and warned that anyone who does not abide by the rules without a reasonable excuse could be fined.
Director of Public Health Northamptonshire, Lucy Wightman, told the BBC : “The factory will close voluntarily.”
“Most employees and their direct households will be required to isolate at home for two weeks”.
Northampton’s incidence rate has hit 125.1 per 100,000 people, in the week ending 13 August.
Mrs Wightman said the current situation is “fragile” in the East Midlands town.
She said: “If we don’t keep continuing to work together to reduce the transmission of the virus there is a very real possibility that further and stricter intervention measures and a possible local lockdown will follow.”
A message sent to staff at Greencore, and shared with the BBC, states the company has “decided to put all colleagues working at the Northampton site (and who are not already self-isolating) on a period of 14 days self-isolation”.