Conservative MPs are demanding that Liz Truss explains whether she is sticking to the 2019 manifesto commitment to reduce overall immigration after the resignation of Suella Braverman. In another sign of a major policy fracture within the party, fellow members of the European Research Group voiced support for the former home secretary, who stepped down on Wednesday after expressing reservations about government plans to grant more foreign work visas as part of a plan to stimulate the economy. Reports claimed that Braverman resigned after a furious 90-minute row with the prime minister and her new chancellor, Jeremy Hunt. Sources close to Braverman said she was angry that they wanted her to announce a new plan to liberalise immigration rules to make it easier for the Office for Budget Responsibility (OBR) to say the government would hit its growth targets. Downing Street was unable to confirm it would stick to its manifesto pledge stating overall migrant numbers would come down. The prime minister’s spokesperson said on Thursday: “We have a commitment to control immigration and recognise that, alongside that, economic stability & growing the economy are important.” The government has stuck to its claim that Braverman left government after sending confidential and market-sensitive policy details using her personal email, which is a technical breach of ministerial rules. Addressing the Cabinet Office minister Brendan Clarke-Smith at an urgent question, the Gainsborough MP, Sir Edward Leigh, said in the Commons he had “great confidence in the former home secretary’s determination that we meet our manifesto commitments”. “Can the minister assure us this resignation was entirely due to a technical breach of the rules and there was no policy disagreement between the prime minister and the home secretary?” he said. The Ashfield MP, Lee Anderson, said he was “sad” to see Braverman leave the government. “I am not convinced that cabinet, government and No 10 were totally behind the previous home secretary.” In a pointed intervention, Andrew Bridgen, the MP for North West Leicestershire, asked: “Would the minister outline to the house the government’s current policy on immigration and would he tell the house whether it is under review at the moment?” Scott Benton, the MP for Blackpool South, said Braverman’s resignation was a tremendous loss to those who wished that “one day this government might finally get a grip of the small boats crisis”. “Can the minister confirm that the government’s policy remains the same?” he asked. Clarke-Smith replied: “I can reassure him this government stands firm in tackling illegal immigration. I would also reassure him that he will have seen the resignation letter from the former home secretary where she does outline her reasons and that this was for a breach of the ministerial code, which is why she took the decision to resign.” On Tuesday evening Truss was said to have addressed the backbench group of Eurosceptics. It is understood Braverman was supposed to outline a new immigration policy to the cabinet on Thursday but on Wednesday morning attempted to send a copy of the plans to John Hayes, the chair of the Common Sense group of MPs, which has supported the home secretary. She accidentally sent the document to a staff member of the Tory MP Andrew Percy, sources confirmed. The breach was then reported to the chief whip, Wendy Morton. The email was deemed to have twice broken the ministerial code. One section says ministers “have an important role to play in maintaining the security of government business”. Another states: “The internal process through which a decision has been made, or the level of committee by which it was taken should not be disclosed.” Yvette Cooper, the shadow home secretary, told the Commons Tory MPs were “fighting like rats in a sack”. Asking an urgent question in the Commons on the departure of Braverman, she said: “I notice there’s no home secretary this morning unless the member for Bassetlaw [Brendan Clarke-Smith] has been appointed home secretary in the last few hours? Which to be honest, nothing would surprise us at the moment because this is total chaos. “We’ve got the third home secretary in seven weeks. The cabinet was only appointed six weeks ago. The home secretary has been sacked, the chancellor sacked, the chief whip sacked and then unsacked and the unedifying scenes of Conservative MPs last night fighting like rats in a sack. This is a disgrace.”