There’s a reason Brits are now struggling to find pints of milk, packs of salad and bottles of water in the supermarket — and it’s not all due to the "pingdemic.”

Britain’s grocers are facing a perfect storm of Brexit, a record number of people self-isolating (most of them having been pinged by the National Health Service’s COVID-19 app) and soaring temperatures that drive demand for chilled goods and wreak havoc on store refrigeration systems. All of this is leading to stocks on shelves running low.

Even before the highly contagious delta variant started spreading, the U.K.’s food supply chains were straining from Brexit.