Labour will be pushed to act on abolishing the “indefensible” two-child benefit limit, the former shadow chancellor John McDonnell has claimed, after Keir Starmer suspended him and six others for the first rebellion of the new government. It came as multiple MPs expressed shock and dismay at the suspensions, including one suspended MP who claimed she felt her experiences of domestic abuse had been “weaponised” in conversations with the whips. Labour said it did not recognise those allegations. Writing in the Guardian, McDonnell said the rebellion was not a coordinated attempt to undermine the government by voting on the SNP amendment, but said it was a genuine point of conscience for those with high levels of child poverty in their constituencies. “The seriousness of the risk demonstrates the seriousness of the issue at stake,” he said. McDonnell and others, who have had the whip suspended for six months for their vote on the king’s speech amendment, said they also had grave doubts about the effectiveness of the child poverty taskforce announced by the government before the vote. McDonnell believes the rebellion and the attention it has focused on child poverty means that the government will eventually have to address the cap, and made it significantly more likely that it will be abolished. Starmer’s political spokesperson confirmed the prime minister had been consulted on the move. “We’ve been very clear on our position on the two-child limit, and why we did not commit to removing it both during the campaign and since,” she said. “And that is because given the economic situation we’ve inherited, we are very clear that we are not going to make promises that we can’t keep. Now clearly voting against the party’s position on the king’s speech is a serious matter.” Earlier this week the education secretary, Bridget Phillipson, had said the taskforce would consider scrapping the limit – as part of a range of options – and was backed by the prime minister. But on Wednesday the government made clear that there was no deadline for the taskforce to report ahead of the expected October budget. MPs said they were concerned there appeared to be no confirmed formal role for the charities such as Save the Children and Barnardo’s who were consulted by the taskforce, many of whom back scrapping the cap. “We’ve been asking and asking, but so far there’s no timescale, there’s no terms of reference, there’s no list of participants,” one MP said. “Some of the charities say they have heard nothing. It feels a bit like it was set up just so they can say: ‘Oh, let’s wait and see what the taskforce says.’” McDonnell said that was among his key reasons for not backing down on the vote. “The concern grew that the reason for not committing to scrapping the cap was not either funding or the timescale for practical implementation by the taskforce,” he said. “Instead, the fear is that it was the behind the scenes party strategists looking at the polls and focus groups, seeing that the cap was popular among some potential supporters and not wanting to alienate them were willing to turn a blind eye to a few hundred thousand children in poverty.” Labour has said it will shortly set out the timeframe and terms of reference for the taskforce, which will hear from external experts. McDonnell denied it was “futile or gesture politics” to vote for the amendment and therefore lose the whip. “It has demonstrated that MPs, if they believe something is right, are willing to risk everything and stand by their cause.” Along with McDonnell, Labour also suspended Rebecca Long-Bailey, Apsana Begum, Richard Burgon, Ian Byrne, Imran Hussain and Zarah Sultana. Kim Johnson, the Liverpool Riverside MP who tabled her own amendment on scrapping the two-child limit but did not rebel to back the SNP’s version, said she was “really sad” at the party leadership’s actions. “I think they need to reflect on the decision, and why and how it was made,” she said. “We need to know if this is the way things will be going forward in terms of taking away the opportunity to debate or challenge. As MPs, we’re there to represent our constituencies, and if people really believe that the party isn’t doing what it should for the most vulnerable, then what course of action is available to us?” Multiple MPs said the anger about the handling of issue went beyond the party’s left, with some saying it tied into wider worries about the team around Starmer. “You’re either in or you’re out. Removing the whip felt a bit like a tactic to scare the new MPs,” one said. Begum told Times Radio that her experiences as a survivor of domestic abuse and alleged intimidation during her election campaign were alluded to in her conversations with whips. “I certainly felt that my experiences were being weaponised against me in this situation,” she claimed. “Effectively to say that support for me as a survivor of domestic abuse was contingent on how I was voting yesterday was shocking.” A Labour party spokesperson said: “We do not recognise these allegations.” Sultana told ITV’s Good Morning Britain earlier on Wednesday that she and her colleagues had been the victims of a “macho virility test”. But the former Labour MP Jon Ashworth said although the cap was “vicious and heinous”, it was appropriate for the rebels to lose the whip on a matter so symbolic as a Labour government’s first king’s speech. “It is their responsibility to defend the Labour position in the voting lobbies of parliament and not vote with the opposition, odds and sods.”