In Islamic tradition, it is forbidden for Muslims to change faith, an act known as apostasy. One Christian charity claims this is threatening freedom of belief in Britain.
Hannah moved home 40 times in seven years to hide from her family
Hannah (not her real name) is under police protection after her family made death threats against her for converting from Islam to Christianity.
She said a large group of men armed with knives, sticks and hammers had come to the house where she was living after her conversion.
"I was home alone, they came to the front door," she said.
"They were shouting 'traitor' and all sorts of things like: 'We're going to kill you.'"
Hannah ran up the stairs, hid under the bed and prayed while they banged on the door.
I would say to my parents I was praying, but actually I was in my room watching Neighbours
"Ten minutes later they went, and I was in one piece. I couldn't believe I was still alive."
Hannah, who is now 31, told her story at the launch of a new charity, Lapido Media, which aims to promote informed debate about faith and freedom of belief.
She was born and raised in the north of England by Pakistani Muslims. Her father was imam at the local mosque.
Islam was central to family life and she describes her upbringing as "very strict".
But Hannah was rebellious. As a teenager she revolted in traditional adolescent fashion by drinking and playing truant.
She first questioned her religion when she was 13.
"I believed in God but the sort I believed in was very different to the one I believe in now," she says.
"I believed I was going to hell if I continued with Islam, as I saw it you had to be a good person.
"I would say to my parents I was praying, but actually I was in my room watching Neighbours."
'Relief and freedom'
Then, when she was 16, her family arranged a marriage for her.
Hannah wanted to go to university and pursue a career, not move to Pakistan to become a wife and mother.
She says: "When I overheard a conversation about it, I decided I was going to have to leave. There was no way I was going to get married. I went to school that morning and I didn't go back."
For a week she slept on the streets. She couldn't turn to any friends as they all knew her father.
"I felt a mixture of relief and freedom, but I was also terrified because it was a different culture and I was out on my own in the world."
Her religious education (RE) teacher took her in, which is when she discovered Christianity.
She attended church against her teacher's wishes, and decided she wanted to become a Christian.
"Three years after becoming a Christian I decided to get baptised. That's when the death threats started," she says.
After the mob attacked her teacher's house, Hannah left, and over the next seven years she moved 40 times.
She relocated to the south of England, where she felt safer, before getting back in touch with her family, hoping they had changed.
She says it went well for about a year, but then they started to get aggressive again.
"About a month ago I got another threat from my brother, saying unless I go back to Islam he would not be responsible for his actions. This was the first time I got the police involved."
In some ways, Hannah's life has met her early aspirations. She has trained to be an RE teacher, and plans further study.
"I am trying to do the things I want to do. I have travelled a lot around the world and want to do more," she says.
But the threats of violence have left their mark, and led her to speak out.
"We all have a responsibility to deal with the issue, not just governments. We have more and more freedom, but for some women this involves being threatened.
"If people convert, choose to follow another religion, they can be killed."