The Harry Potter author JK Rowling has spoken about the abuse she suffered at the hands of her former husband, saying he tried to lock away the unpublished manuscript of the series’ first book to stop her leaving him.

Speaking on the Witch Trials of JK Rowling, a podcast series released on Tuesday, the author described her relationship with Jorge Arantes as violent and controlling, saying she had to sneak pages of the work away in small batches to photocopy in case he burned them.

“At this point he’s searching my handbag every time I come home. I haven’t got a key to my own front door because he’s got to control the front door. And I think he’s not a stupid person. I think he knew, or suspected, that I was going to try and bolt again,” she said.

Rowling described living in “a horrible state of tension” with Arantes because she had to hide her desire to leave him. “And yet the manuscript kept growing. I’d continue to write. In fact, he knew what that manuscript meant to me because at one point he took the manuscript and hid it and that was his hostage.”

Becoming increasingly determined to leave, she would secretly “take a few pages of the manuscript into work every day – just a few pages so that he wouldn’t realise anything was missing – and photocopy it”.

She added: “And gradually in a cupboard in the staff room, bit by bit, a photocopied manuscript grew and grew and grew, because I suspected that, if I wasn’t able to get out with everything, he would burn it or take it or hold it hostage.

“That manuscript still meant so much to me. That was the thing that I actually prioritised for saving. The only thing I prioritised beyond that, obviously, was my daughter, but at that point she’s still inside me, so she’s as safe as can be in that situation.”

Rowling was speaking to Megan Phelps-Roper, a former member of the Westboro Baptist Church, which is known for its hateful views and frequent protests against the LGBT community and other marginalised communities. After leaving in 2012, Phelps-Roper wrote Unfollow; a memoir detailing her experience of “loving and leaving extremism”.

In a series of tweets about the podcast series, Rowling said she agreed to take part after Phelps-Roper approached her because she felt the pair could have a “real, interesting, two-sided conversation that might prove constructive”.

Speaking on the same podcast, the author addressed her stance on gender issues, saying she had not set out to upset anyone. “However, I was not uncomfortable with getting off my pedestal and what has interested me over the last 10 years, and certainly over the last two, three years, particularly on social media [is people saying]: ‘Oh, you’ve ruined your legacy. You could have been beloved for ever.’

“And I think: you could not have misunderstood me more profoundly. I do not walk around my house thinking about my legacy. What a pompous way to live your life walking around thinking, what will my legacy be? Whatever. I’ll be dead. I care about now. I care about the living.”

Among those to criticise her take on gender identity are the stars of the Harry Potter film franchise Daniel Radcliffe, Emma Watson and Rupert Grint.

Some critics have accused Rowling of stirring transphobia, including through her mocking interventions on social media.

Rowling said she had received “so many death threats I could paper the house with them”.

• In the UK, call the national domestic abuse helpline on 0808 2000 247, or visit Women’s Aid. In Australia, the national family violence counselling service is on 1800 737 732. In the US, the domestic violence hotline is 1-800-799-SAFE (7233). Other international helplines may be found via www.befrienders.org