The leadership candidate explained her stance after signing up to a campaign to “fight” women’s groups deemed to be “transphobic” and for offending party members to be expelled.
“There is no conflict between rights of women and the protection of women, and safety in particular places, and trans rights,” Ms Long-Bailey argued.
“And we need to stop having this debate within this party on that basis ... there doesn’t need to be a differentiation between the two.”
She called for changes to the 2010 Equality Act, which allows exclusions from women-only spaces, saying: “I want a right to self id [identification] for trans people, it’s not an easy journey to go on.”
It was put to Ms Long-Bailey that female victims of domestic violence have spoken of their “debilitating terror” and of the vital importance of a woman-only refuge.
But she replied: “We can’t use that as an argument to discriminate against transpeople.”
The BBC’s Andrew Marr suggested that – if holding such views triggered expulsion – “an awful lot of good feminists inside the Labour party would be caught by this”.
He quoted Jess Phillips’ support for women-only spaces, asking: “Jess Phillips could be kicked out of the Labour party if Rebecca Long-Bailey becomes leader?”
The leadership hopeful replied she didn’t believe her former rival had said “anything transphobic” and said it was “right to listen to concerns about domestic abuse”.
The interview laid bare how the controversy has exploded into the leadership debate, after Ms Long-Bailey signed the 12-point charter put forward by a group called Labour Campaign for Trans Rights.
It demands the expulsion of anyone putting forward “bigoted transphobic views” – naming Women’s Place UK and the LGB Alliance as “transphobic organisations” that must be resisted.
Women’s Place, a group of Labour members campaigning to keep women-only refuges and other spaces, fiercely denied it was transphobic and called the accusation “defamatory”.
Ruth Serwotka, the group's co-founder, has now written to leadership candidates demanding to see the evidence behind the claim.
“I hope you understand that expulsions of women from the party on the grounds you are suggesting (and being cavalier about evidence) will provoke a huge backlash,” she wrote.
“It will be fiercely opposed by all fair-minded members, who insist on reason and evidence.
“In fact, we are a women’s rights organisation committed, among other things, to upholding current sex discrimination and equality law as set out in the Equality Act (2010), including upholding protections for trans people”.
In the interview, asked about Women’s Place, Ms Long-Bailey insisted: “I’m not regarding any particular group as a hate group.”
Mr Marr replied: “You signed something that said so?”
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