The UK’s illegal migration bill could mean modern slavery victims are less likely to give evidence against traffickers, Theresa May has said. The former Conservative prime minister warned MPs that slave drivers and traffickers will find it easier to escape justice under Rishi Sunak’s immigration plans. Speaking during the second day of the bill’s committee stage, May called for modern slavery victims to be excluded from measures within the prime minister’s flagship bill. “My fear with this illegal migration bill is that it will drive a coach and horses through the Modern Slavery Act, denying support to those who have been exploited and enslaved, and in doing so making it much harder to catch and stop the traffickers and slave drivers,” she said. May also appealed for talks with the government to resolve her concerns, adding that she feared there had been a “lack of proper consideration of slavery” and the experience of survivors from the government. She said: “There is a move that would be of more benefit in enabling us to catch the slave drivers and support victims and survivors, which would be to ensure those in slavery here in the UK were excluded from this bill. “That would mean recognising the intention of the Modern Slavery Act – that those who have been here in slavery in the UK should be protected by the act regardless of their immigration status. “Now, there may be some of my colleagues who might say, ‘Well, doesn’t that mean an awful lot of people are going to want to stay here?’ and worry about the numbers, but many people brought here into slavery actually want to go home, they don’t just want to stay here. “Under this bill, I fear it is more likely that they will stay here in the UK and be staying here in slavery.” Temporary protection against removal from the UK is currently given to suspected victims of modern slavery or human trafficking while their case is considered. However, the bill seeks to remove protection for people who are judged to have entered the UK illegally, with an exception for those cooperating with a criminal investigation. It comes as more than 60 NGOs, MPs and academics wrote to Sunak urging him to withdraw the bill, warning that it will drive modern slavery underground and “cost lives”. Signatories, including Anti-Slavery International, After Exploitation and Liberty, say it would “rob” people fleeing danger of the right to claim asylum, simply for entering the UK irregularly.