A union representing hundreds of clerks, security guards and kitchen staff in parliament is threatening strike action following chaotic scenes on the parliamentary estate as MPs queued to vote on Tuesday. Officials from the PCS union have told parliamentary authorities that they could recommend balloting their members following the failure of MPs to distance themselves from staff as some waited for more than an hour to cast their votes. The union is especially concerned because more than a third of their members in parliament are BAME. People from ethnic minorities are at a higher risk of dying from coronavirus according to Public Health England. The development came as ministers come under increasing pressure to ditch its return to a physical parliament after weeks of allowing MPs to attend remotely via video link. Critics rubbished the government’s current arrangements on Wednesday night after the business secretary, Alok Sharma, confirmed he was being tested for Covid-19 after appearing to be unwell while delivering a speech to the Commons. Government sources confirmed that the house authorities are looking at alternative methods of allowing MPs to vote that could speed up the voting process. Chaotic scenes unfolded in the Commons on Tuesday when MPs formed a long queue snaking through parliament so they could maintain physical distancing while voting on the motion. Union officials said it resulted in a series of complaints from members. One member complained about a lack of physical distancing at and around the underground entrance to the Commons, where MPs were photographed by colleagues standing less than a metre away from each other. “It was a breeding ground for infection. Supermarkets have better Covid management in place,” the source said. A security source said that the risk assessment shown to some staff showed that the parliamentary authorities do not have a method of controlling the number of people on the estate. “The risk assessment is only there to facilitate a poor decision by the government,” the source said. PCS officials wrote to the parliamentary authorities saying that a failure to comply with five tests, could result in industrial action. The five tests include a promise to track and trace those in contact with an infected person, regular Covid-19 tests for staff, and a pledge to carry out a Covid-19 risk assessment including an equality assessment to examine the impact on BAME workers. Mark Serwotka, the general secretary of PCS, which claims to have around 800 members across the Palace of Westminster, said: “The decision to scrap the hybrid parliament has been a disaster. “We will support our members wholeheartedly if they decide to take action and the blame will squarely lie with [the leader of the Commons] Jacob Rees-Mogg.” Sharma’s potential case of Covid-19 in the chamber came a day after MPs approved the government’s plan to end virtual voting in the Commons. MPs are due to debate a motion laid by Rees-Mogg on Thursday to allow those who are shielding and those aged over 70 to vote by proxy. The Northern Ireland secretary, Brandon Lewis, said it would be premature to suggest Sharma had the virus. Speaking to BBC Radio 4’s Today programme, Lewis said: “I don’t want to be premature because Alok, who I wish well and hope he recovers quickly, may well have had severe hay fever, we’re not sure yet.” Government sources said MPs could abandon the system of filing through the chamber to cast their votes, which led to long queues. According to the BBC’s Newsnight, one option being examined would be to let MPs swipe their security cards on a reader in the division lobbies, where they traditionally assemble. A House of Commons spokesperson said: “Our priority is to ensure that those on the estate are safe while parliamentary business is facilitated. We are taking every step possible to limit the number of staff who have to physically return to the building and are meeting regularly with representatives of the trade unions.”