British supermarkets urged shoppers against panic buying as shelves emptied because of supply problems with thousands of staff forced to isolate during the Covid-19 pandemic. The major retailers said they were all facing major supply problems with an increasing number of staff and drivers forced to take time off after coming into contact with someone infected with the virus. The UK’s biggest supermarkets described any shortages as “patchy” across stores but said there was no need for customers to change their shopping habits. More than a million people have been forced to isolate – including about 620,000 who were "pinged" by the government’s Covid mobile phone app in the week to July 14 on top of around 500,000 the week before – causing problems across a range of industries. A shortage of lorry drivers led to supply problems at petrol stations run by oil giant BP while some councils have been forced to stop refuse collections because of staff shortages. Some train companies have reduced services because of drivers being forced to stay at work. Mail deliveries have also been affected. The problems – collectively described as a "pingdemic" because of the role of the app – come in the week that the government announced Freedom Day, with the lifting of most legal restrictions aimed at limiting the spread of the virus. Kwasi Kwarteng, the business minister, said the government would intervene to grant all specialist workers exemptions from isolation rules. "We’re looking at different sectors and we will be publishing today the sectors that will be affected," he said. But he said the government was “very concerned about the situation and was monitoring it. Prime Minister Boris Johnson is among those self-isolating for 10 days after being pinged by the app after Health Secretary Sajid Javid tested positive for the disease. Critics say the system has means thousands of perfectly healthy people are forced to remain at home – but the government pointed to data that showed one in three people self-isolating because of contact with a positive case went on to develop symptoms. Industries suffering from shortages are calling for exemptions for key workers to keep the flow of goods moving. The problems are most obvious in supermarkets, where shoppers have posted photos of shelves stripped bare. Richard Walker, the head of the Iceland chain, said that the problems had forced a couple of shops to close. The company is employing about 2,000 temporary workers to try to overcome the problems. He said that “panic buying is only an option for those who can afford it”. “Once shelves are stripped bare it is the most vulnerable who actually suffer.” Britain's second-largest supermarket group Sainsbury's said customers would generally be able to find the products they want, though perhaps not every brand. "We are working hard to ensure customers can find what they need," said a Sainsbury's spokesperson. "While we might not always have the exact product a customer is looking for in every store, large quantities of products are being delivered to stores daily and our colleagues are focused on getting them onto the shelves as quickly as they can." Elsewhere, sandwich chain Pret A Manger has temporarily closed 17 shops due to staff being forced to self-isolate. Andrew Opie, of the British Retail Consortium, said the pingdemic was putting pressure on retailers to keep shops open and shelves stocked. “Retail workers and suppliers, who have played a vital role throughout this pandemic, should be allowed to work provided they are double vaccinated or can show a negative Covid test, to ensure there is no disruption to the public’s ability to get food and other goods.” Industry sources said the haulage sector was down about 100,000 drivers from current demand levels. The head of a food distribution company said it was ignoring government guidance to advise drivers to continue working even if they had been pinged by the app after taking tests. Bidfood chief executive Andrew Selley told the BBC that he was taking the approach because his staff were “critical workers”. "We operate in Covid-safe workplaces and we're absolutely key workers in terms of the supply chain to hospitals, care homes, prisons, and therefore it's important for us to be able to keep offering that service to our customers,” he said.