Lisa Nandy has defended her strong support for transgender rights after JK Rowling criticised her as “one of the biggest reasons many women on the left no longer trust”.

The shadow international development secretary said on Thursday that the furore “breaks my heart” as she re-reads Harry Potter with her son following the author’s attack.

The MP insisted women can trust the Labour Party and said that people will be “utterly ashamed” to look back on the reduction of the debate to bodily parts.

Rowling, whose outspoken views on gender issues have seen her called transphobic, which she has denied, criticised Ms Nandy after she said women’s rights are “non-negotiable”.

“You said rapists should be transferred to women’s prisons if they self-identify as women,” the author replied on social media.

“You called Woman’s Place UK a hate group. Given that you’re one of the biggest reasons many women on the left no longer trust Labour to defend their rights, do you stand by these comments?”

Ms Nandy, in 2020, previously backed a pledge card calling on the party to expel “transphobic” members and described campaigns including Women’s Place as “trans-exclusionist hate groups”.

Asked at an event with members of Westminster’s press gallery if women can trust Labour, the MP said: “Yeah, look, they can.”

“It breaks my heart actually, we’re re-reading Harry Potter at the moment in my house with an eight-year-old who is absolutely Harry Potter obsessed.

“And I don’t think we should end up in an oppositional relationship where we’re talking about some of the most marginalised, discriminated against women and girls on the planet and we can’t have that debate, because there’s a genuine conversation to be had about the rights of transgender people and the protection of safe spaces and hard-fought rights for women.”

She said the debate surrounding transgender issues and women’s rights needs “far less heat and far more light”.

“And I genuinely think when I look at the way the debate is conducted, the way that so much of this is based on fear and creating fear about a group of people who are having a very, very tough time,” she said.

“When we look at the way we reduce the debate to things like bodily parts, I think when we look back in history we will be utterly ashamed of ourselves.”