Boris Johnson has admitted he is unsure what is causing coronavirus outbreaks in meat processing factories - but that the government is investigating.
It comes a day after it was reported that a local lockdown could be enforced in Anglesey to prevent an outbreak at a meat processing plant on the island spreading further.
A total of 158 people who either work at or have links to the 2 Sisters chicken processing plant in Llangefni, Anglesey have tested positive with Covid-19.
A region of Germany has also been forced to impose a week-long local lockdown due to an increase in coronavirus infections linked to a slaughterhouse, officials said.
More than 1,500 people tested positive for coronavirus at the Toennies slaughterhouse in Rheda-Wiedenbrueck and thousands more have also been put under a quarantine to try to halt the outbreak.
Following his speech in the House of Commons, in which he announced a series of huge changes to the UK's current lockdown measure, the Prime Minister took questions from MPs.
SNP's Martyn Day asked him how reducing social distancing from two metres to one metre will impact on the factory situation.
Mr Johnson responded to the Commons: "We're looking at exactly what’s happening in meat processing plants.
"There are currently, I think, two theories advanced to me – one about the cold environment in the plants may be propitious to the virus, the other is the possibility that staff are congregating in such a way to spread the virus.
"I don't know what it is, we are investigating.
"But wherever these outbreaks take place, we will use local cluster-busting techniques to stamp them out."
