Labour’s selection process for a new metro mayor has been plunged into acrimony after a leaked email showed that the shadow minister Naz Shah has accused a prospective candidate of being unfit for office.

Shah, the shadow minister for women and equalities, is demanding that Salma Yaqoob should not be allowed to stand as mayoral candidate for the West Midlands. Shah claims Yaqoob should stand down because she ran a “despicable” general election campaign against her in Bradford West two years ago.

Yaqoob, a former Birmingham councillor backed by Momentum’s leader, Jon Lansman, hit back, saying that Shah has refused to accept her public apology for standing as a Respect candidate, and is instead recycling vexatious claims.

Salma Yaqoob said Shah has refused to accept her public apology. Photograph: Christopher Thomond/The Guardian

The row has been ignited after Labour’s national executive committee (NEC) gave Yaqoob permission to oppose the MP Liam Byrne and unions’ favourite, Pete Lowe, in the race to be selected as the party’s official candidate to take on the West Midlands Conservative mayor, Andy Street.

Shah has written to the NEC this week claiming Yaqoob endorsed a campaign of misogyny, patriarchy and clan politics in 2017.

Shah claimed she was driven to contemplate suicide after Yaqoob’s campaign exploited patriarchal politics, or biradri, among the city’s Kashmiri and Pakistani community.

“This kind of clan politics, not underpinned by any political ideology but driven by men for the purpose of men to gain and retain power, has hindered the development of my city,” she said.

“Despite giving me her word that she wouldn’t come to Bradford West after I explained this to her in detail, SY [Salma Yaqoob] still came and stood against me. In doing so I believe she endorsed misogyny, patriarchy and biradri politics.

“If that wasn’t a betrayal enough by a Muslim woman who I once looked up to, SY then allowed a local imam at her campaign launch to ‘hijab shame’ me. ‘Who is the most Muslim, that is Salma Yaqoob,’ were his words whilst SY sat there and applauded,” she said.

Shah claimed that Yaqoob’s campaign exploited Shah’s unconventional background – a divorcee raised on benefits by a single parent with a mother who was imprisoned for killing a man who had abused her – to win votes.

“I feel that SY used my backstory to literally dishonour me, making me ‘unworthy’ within the community. She did this in full knowledge of the cultural dynamics of honour, patriarchy and misogyny,” Shah said.

“To be questioned whether I was good enough by a bunch of patriarchal men, the misogynists in my community, in public, putting my character on trial for the sake of political gain with not a single word of condemnation but applause from SY is despicable,” she said.

Shah, who included recorded clips of Yaqoob from 2017 in her submission, claimed the campaign drove her to consider suicide.

“This personal attack on my honour and everything I stood for … made me feel suicidal on two occasions during that campaign,” she said.

In the email, the MP for Bradford West has accused her own party of giving Yaqoob “special treatment” so she could stand to become a metro mayor.

Labour sources insist the party went through the proper processes and Yaqoob’s candidacy was waved through because there were no other women or BAME candidates.

Approached for a comment, Yaqoob denied ever exploiting Shah’s background, adding that it was “disturbing and manipulative” to say so. Yaqoob said she had consistently campaigned against the clan system and did not try to shame anyone.

She said in a statement: “I would like to move forward in this campaign by recognising the problems of the past, honouring the pain felt on all sides and building collective support to deliver the very best for the people of the West Midlands under the Labour party.

“I have always had an open-door policy and have not shied from taking constructive criticisms on board. I would like the opportunity for Naz to see the journey I have been on over the last couple of years, perhaps this is something that I can only demonstrate through actions rather than words.”

• This article was amended on 2 October 2019. Salma Yaqoob is no longer a Birmingham city councillor. She served on the council between 2006 and 2011.