Theresa May has launched a double attack on Boris Johnson’s government, speaking in the Commons to first warn about the security implications of a final no-deal Brexit, and then against the coronavirus quarantine plans. May, who has largely kept a low profile since returning to the backbenches, used prime minister’s questions to express worry at a lack of possible lack of intelligence and data sharing if the Brexit transition period ends without a formal agreement. The government had, May began, “rightly been focused on keeping people safe” over coronavirus. “But that task goes beyond Covid-19. So can my right honourable friend give me the reassurance that as from 1 January 2021, the UK will have access to the quantity and quality of data it currently has,” she said, citing areas such as air passenger name records. Johnson replied: “That depends, I’m afraid, on the outcome of our negotiations, as she knows well. But I’m absolutely confident that our friends and partners will see sense in the great mutual benefit of continuing to collaborate in exactly the way we do.” Twenty minutes later, May expressed her concern again, this time more openly, adding her criticism of the government’s new 14-day quarantine system for overseas arrivals, which begins next week. The former prime minister said the aviation industry sustained millions of jobs. “International air travel is necessary for trade,” she said. “Without it there is no global Britain. So instead of bringing in measures to close Britain off from the rest of the world, why is the government not taking a lead in developing an international aviation health screening standard, to save jobs and ensure that Britain is open for business?” The interventions herald two potentially difficult areas for Johnson in the coming weeks and months. The latest round of Brexit talks are under way this week, but with few signs of an imminent breakthrough in areas such as mutal standards and fishing rights. The former prime minister is likely to be among a number of Tory MPs who would express concern if a no-deal end to the transition period may mean the UK losing access to data and information sharing in areas such as security. More immediately, a number of Conservatives are angered by the quarantine plan, saying it will provide little public health benefit, and will badly affect the travel and aviation industries. May criticised the plan during an urgent question on quarantine in the Commons from Huw Merriman, the Tory chair of the transport select committee, who is a persistent critic of the scheme.