The director of a documentary about Sinead O’Connor’s life has told of the impact the singer had on her.

Nothing Compares traces O’Connor’s turbulent life from her childhood in Dublin in the care of a mentally ill mother and her subsequent journey through the care system.

It tells the story of O’Connor’s war of attrition against an image-obsessed music industry that tried and failed to tame her and led to further outbursts, including repeated criticism of the Catholic Church.

Archive material and testimony from friends and musical collaborators illuminate a career stretching over five decades.

Director Kathryn Ferguson told BBC Radio 4’s Front Row show on Wednesday that she was “devastated” to hear the news of the singer’s death.

“I just found out an hour ago. I’m devastated to hear the desperate news about Sinead,” she said.

“Our film, really for me, it was a love letter to Sinead. It was made over many, many years. And made because of the impact she had made on me as a young girl growing up in Ireland.”

Ferguson said that she first came to know of O’Connor through her music.

She said: “It was through her music, my father introduced me to Sinead’s music in the late 80s, her album The Lion And The Cobra was played on repeat as we drove around Belfast in the late 80s, and it became this visceral soundtrack to my childhood.

“Then in the early 90s my friends and I really discovered her for a second time and could really see how she looked, heard what she had to say, and she became this huge icon of ours, and someone we were so proud of.”

Ferguson said that it was soon after she discovered O’Connor that the backlash against the singer began.

Speaking to The Graham Norton Radio Show on Virgin Radio on Sunday, the director said that one of the focal points for the documentary was the moment the singer tore up a photo of Pope John Paul II during an appearance on Saturday Night Live in 1993.

Ferguson said the documentary examines “why things happened as they did”.

“Well, we always had the plan to tell this part of her story, which really focuses in from 1987 to 1993,” she said.

“We really wanted to look at why things happened as they did, ie, the horrendous fall like that happened after she ripped up the picture of the Pope on Saturday Night Live in 1993.

“And the reason for that was just that it seemed to cause so much confusion at the time.

“And so much of our film is about trying to go back and look at the cause and effect, really, behind why she did that, and why it was such a political powerful act. But why she was treated the way she was afterwards as well.”

Ferguson said that O’Connor was labelled a “devil” after she tore up the picture.

“She really was. I mean, there was very much an attitude of burn the witch, post that act on Saturday Night Live. And I think it’s that part of the film where you can actually hear audible gasps in the audience, because it’s still very horrifying.”

Given a small cinematic release last year, the documentary will be released on Sky Documentaries and streaming service Now on Saturday.