“Growing up was challenging,” says Melody, 55, a former TV presenter turned author and public speaker.

“Domestic violence was rife. I held my breath waiting for the next row. Mum showed affection and tried her best. But to my father, I didn’t exist.”

Melody lived in Cornwall with her mother, father, two older sisters and older brother, until she was seven, when the family relocated to Adelaide, Australia.

“Dad got a job and that was it. My brother and I flew out in 1976. My sisters were nine years older than me so stayed behind. Leaving them and the familiarity of home – as awful as it was – was distressing,” says Melody, who now lives in Melbourne with partner Grant, 58.

Once in Australia, the violence escalated. “I would have to prise them apart. Sometimes I’d get whacked in the crossfire. The police were a constant presence,” she says.

“I found it hard to socialise and was an outsider. My father told me I wasn’t going to make anything of my life, and I didn’t have a lot of self belief. But at the same time there was a little fire in me that pushed back – I wasn’t ready to give up the fight.”

At 16, Melody and her mum finally left.

She says: “I could see that someone was going to die, so we moved into a flat. My brother had already gone to study nursing.”

But soon, her father began turning up outside the flat in different disguises.

“I felt someone watching me. Peeking through the window, I saw him in the car. It freaked me out.”

Melody’s mum got a restraining order, but the stalking continued, and one day, when Melody was 17, he attacked her mum with a corkscrew, before slashing his own throat.

“Everything happened in slow motion, I had to pull the corkscrew out of my mum,” says Melody.

“The police and ambulance turned up and took them both away. He was charged, and the next time I saw him was in court – when I had to testify against him.”

Melody’s father was sentenced to 18 months in prison, during which time he was diagnosed with paranoid schizophrenia. A year after his release, he took his life. Melody was 19.

“It was a few days before my final exams. It was a shock, and sad of course, but, in some ways a relief. I decided to sit my exams, although the college said I didn’t have to. I wanted to change my life.”

In 1987, Melody started a degree in communications at the University of South Australia and met conservationist Mike Bossley.

“He gave a psychology lecture I went to, and told us about a project researching a pod of bottlenose dolphins who lived at the mouth of the Port River in Port Adelaide. Something in me clicked. I asked if
I could help.”

On her first trip she met one dolphin in particular – Jock – that would change her life for ever. “I couldn’t believe Jock was a dolphin when I first saw him – his dorsal fin was so mangled. Dolphins are social creatures but Jock was alone, in a part of the river separate from all the others. He would circle our boat and interact when he saw us,” says Melody. “It seemed so sad, but something in me understood him. I felt connected to this wild animal and felt a surge of compassion. I knew his loneliness.”

Over the next three years, Melody swam with him often.

“When you’re in the water with a wild animal there’s an element of trust you have to have. To allow myself to trust was a remarkable thing. He allowed me to feel vulnerable again.

“I’d never experienced unconditional acceptance before
in my life. This dolphin wanted nothing of me other than to interact and to hang out. It was amazing – mind-blowing even.

“Every relationship I’d had previously had conditions and baggage, but with Jock it wasn’t like that. For the first time in such a long time I could just be myself.”

Slowly, Melody began to heal.

“I’d had therapy after the attack, but Jock was like natural therapy for me. He taught me to live in the joy of the moment, not to dwell on what had been in the past,” she says.

In time, Melody, Mike and the team were able to coax Jock to join the other dolphins in the river.

“Little by little, he’d follow us further and further. It taught me a lot about bravery, stepping outside of my comfort zone.”

Eventually, he started integrating with other dolphins, and the last time Melody saw Jock he ignored her.

“He was with his dolphin friends, the way it should be,” she says.

Waving goodbye to Jock felt like closing a chapter on her old life, ready to start a new one.

Inspired, she teamed up with Mike to start a not-for-profit to raise funds for more research for the dolphins.

Being interviewed led to a career in TV as an environmental reporter.

“I felt like a fish out of water, but, like Jock, little by little I found my tribe,” says Melody.

This month sees the launch of Melody’s memoir, The Dolphin Who Saved Me.

“Mum understands why I want to tell my story. You can’t change what has happened but you can help other people,” she says.

“I made a decision not to be defined by my past – I was the victor rather than the victim.

“Thanks to Jock I found my purpose. He went out of his patch, and little by little I discovered my freedom. I’ll forever be grateful to that little dolphin.”

The Dolphin Who Saved Me: How an Extraordinary Friendship Helped Me Overcome Trauma and Find Hope, by Melody Horrill (£14.99, Greystone Books) is out now