Tensions have flared within the Labour party as two members of Keir Starmer’s shadow ministerial team were pitted against junior leftwing MPs in battles to win the nomination for new parliamentary seats. Gerald Jones, the shadow Welsh minister, won a selection contest for the new seat of Merthyr Tydfil and Upper Cynon on Wednesday against Beth Winter, an MP from the leftwing Socialist Campaign group. Winter had described it as an “undemocratic” process after her constituency of Cynon Valley was effectively merged with the Merthyr Tydfil and Rhymney constituency that Jones had represented since 2015. Separately, Alison McGovern, a shadow work and pensions minister, is in a contest against Mick Whitley, another leftwing MP in the Socialist Campaign group. McGovern’s Wirral South seat is being abolished, so she is standing for selection against Whitley in his seat of Birkenhead, where the boundaries have been redrawn. The battles have come about because of a shake-up of constituency borders by the Boundaries Commission, reducing the number of available seats. It has left many neighbouring MPs vying for nominations in the new constituencies. The race in Merthyr Tydfil and Upper Cynon was extremely close. Jones won by 16 votes overall with 231 voting for him and 215 backing Winter. Jones said he was “incredibly grateful” to have won his selection, as “Britain is crying out for a Labour government”. He said he would “work flat out to make Keir Starmer our next prime minister”. The shadow minister also paid tribute to Winter for presiding over a “comradely campaign” before calling on his colleague to “unite Merthyr Tydfil and Upper Cynon and win for Labour”. Winter has criticised the “unjust” and “unfair” handling of the process. “Unacceptable obstacles were placed in the way of this grassroots campaign, undermining the democratic process. The online-only process was bulldozed through in just two weeks, with no face-to-face hustings. This was not a fair contest, and I will be taking advice and soundings in the days ahead about my next steps,” she said after her deselection. Before the selection battle in Birkenhead, McGovern, Gordon Brown’s former parliamentary private secretary, voiced concern that the boundary review’s reducing of the number of Wirral constituencies from four to three “will not give them enough attention”, but remained hopeful that MPs in the region “will work together”. Brown attended the Birkenhead constituency with McGovern on Sunday, describing the frontbencher as a “hope for the future”. Whitley was previously selected unanimously by his local party, as was McGovern, who, allies have said, is fighting to represent her home town. Some senior Labour MPs who have supported Starmer since he became Labour leader said the ruthlessness of the latest selection battles have made them uncomfortable. “It’s just not a healthy way to operate a democratic party,” one said. “If the leadership continues in this way, the party will be filled with an army of robots who all think like the leader which isn’t healthy for any thriving workplace.” Another feared the party would not just lack diversity, but a diversity of thought, which could alienate voters and limit how far the party inspired hope and changed lives. A Momentum source said: “The Starmer leadership is exploiting the boundary review to continue his purge of working-class, leftwing Labour MPs, in direct contradiction to his previous commitments to party unity and defending MPs from unnecessary selection battles.” Starmer has faced criticism for U-turning on his position on holding open selections. As a shadow minister, Starmer said Labour should remain a “broad church” which was “one of the great strengths of the party … it has allowed the party to change over time and to remain relevant over the very many years of its history”.