The former shadow minister Sam Tarry, who was deselected as Ilford South’s MP on Monday night, has demanded the party release the names of those who cast electronic votes in his constituency. Tarry lost his reselection battle by a significant margin to the Redbridge council leader, Jas Athwal, who was the favourite to win selection in 2019. Athwal was suspended from the process at the last election because of a complaint that was subsequently dismissed – and Tarry’s selection has been the focus of bitter resentment in the constituency and among many MPs who supported Athwal. The rare deselection of a sitting MP is likely to spark tension in the shadow cabinet. Tarry is the partner of the deputy leader, Angela Rayner, and has been supported by senior ministers including Ed Miliband. Athwal is a close ally of Labour’s Wes Streeting, who has the neighbouring Ilford North seat and had campaigned vigorously on his behalf. Tarry lost the selection by 138 votes, despite briefing he was confident of victory because of a detailed data-driven campaign with a high contact rate with Labour members. In a statement on Tuesday, he said he was “utterly crestfallen by the result” and that the people of Ilford “deserve better than to have been at the centre of a manufactured political circus”. He said he would ask the party to review the date of who voted online in the reselection process – the first step in a potential challenge. “I am extremely concerned about the result, which does not reflect the feeling my campaigners met on the ground talking day in day out to members, or the extensive meticulous data we gathered on the campaign.” Tarry said he was asking the party to share the full information of who cast electronic votes, by what method, and when they were cast, information he said was available in the “anonyvoter” system. “In the meantime, I will continue to represent the people of Ilford South the way I have done for the past three years – with integrity, generosity and inclusivity. Thank you to my amazing team of volunteers on the ground, who are the best of Ilford,” he said. Athwal said the vote on Monday meant the constituency could move on. “It means Ilford can focus on the future and ensure that Westminister delivers for Ilford, that Ilford gets the investment it needs and deserves,” he said. One Labour ally of the council leader said the result had gone overwhelmingly in their favour, calling Tarry “a pound shop Donald Trump” for questioning the result.