He is small enough to need his own taxi, but Maria Johal says Rusty has changed her life.

Rusty is a three-year-old Falabella, one of the world’s smallest horse breeds, and Maria now uses a private vehicle to get him around London.

“He gives me a life,” Maria says.

Maria, 50, says she has spent most of her life suffering panic attacks after developing post-traumatic stress disorder from childhood neglect. She says the attacks left her unable to work, and she began looking for ways to help treat her anxiety.

After researching equine therapy, Maria learned a horse’s heartbeat can sync with a human’s, which she says helps regulate her breathing.

“Panic attacks can be really horrible; he’s really given me a life,” she says. “I was so isolated, now I’m meeting so many more people in my community.”

Rusty is a registered therapy animal and is allowed on public transport, but Maria says he has been too nervous to use it. She says his new ride will help them travel further, with plans to visit a special needs centre and a hospice.

For Rusty’s next trip, Maria says, he is going to the dentist with her.

“He’s a magnet, people just gravitate towards him,” Maria says. “Dogs are amazing, but after researching equine therapy, it’s the right decision for me. You meet your whole community and people outside of it.

“When I walk Rusty, he’s good for the soul. He helps you if you feel blue, if you just need some clarity or perspective on the trials and tribulations of life, he gives you that. But he’s cheeky like any three-year-old.”

Rusty has also helped reconnect Maria with her friend Seamus after the pair lost touch in their teenage years. Seamus, 54, used to be a bricklayer and now trains horses. He has been studying equine therapy and helping train Rusty.

“Maria called me and asked if I’d help her train Rusty. I never imagined I’d be walking a horse in London,” he said.

There is now another small horse in the picture. Tayto is 10 months old and has been adopted by Seamus. Maria and Seamus hope he will also become a therapy horse.

Maria says Tayto had a difficult start in life.

“When we got him, we had to shave him because he was riddled in itchy mites. We found burn marks on his back. With any rescue animal, it’s all about trust; baby steps and love.”

She says Rusty has taken on a protective role around him.

“Rusty guards him at night, grooms him, and wants to protect him. He’s [Tayto] learning from him all the time,” Maria says. “My horse is a therapist for this other little horse now. Every day he blossoms.”

Maria says she now receives Christmas cards for Rusty and that people from all walks of life stop to see him.

“In London, it can take a good few years to meet your neighbours. For centuries, horses have been known to be magical creatures, and it’s true, he gives me life.”

She says she hopes seeing Rusty encourages conversations about mental health.

“I think there are so many people struggling and not enough resources; anyone can become unwell,” she says. “You can develop certain disorders, you don’t always need to have trauma to develop them.

“Not everyone’s dream comes true, not everyone gets to have the children, the Christmas tree and the labrador, life is complex and complicated for every individual. For me, it’s about finding solutions.

“With Rusty, I feel proud; he’s my everything.”

Leah is one of many children who volunteer with Rusty. She says her confidence has grown and that she has learned to walk horses.

“I enjoy playing with Rusty a lot,” Leah says. “I just love him so much. It’s amazing seeing a horse in London; you don’t see them unless you go to the stables.”

Maria says children get the chance to pet Rusty and learn to walk him, something she says brings joy to the local area.

Dr Tracy King, a chartered clinical psychologist, says animal therapy can create the foundation for later talking therapy because once someone is more regulated and stabilised, they may feel safer and more able to explore difficult emotions or experiences.

“For many people, especially those who are anxious, traumatised, grieving, lonely, neurodivergent, or emotionally overwhelmed, talking about their experiences can feel too much at first,” Tracy says.

“Animals can offer a calming, non-judgemental presence that helps a person feel safer, more grounded and more connected.

“Stroking an animal can also stimulate the release of oxytocin, often called the bonding hormone, which is linked to feelings of trust, safety, warmth and connection.”

Read more from BBC News.