A pet dog named Odin helped Jolyon Ellwood-Russell and his wife Jen through a dark time after a severe antibody reaction to cancer attacked Jolyon’s brain, leaving him unable to walk and forcing him to give up his acclaimed legal career.

Now, having had the Australian Labradoodle trained as a disability assistance dog by the national charity Support Dogs, both Jolyon and Jen have the reassurance that help is always at paw.

Trained by the Yorkshire-based charity, Odin can open and close doors, pick up items that Jolyon drops, help him to undress, push access buttons for lifts and doors, and fetch help. The pair recently graduated as a successful Support Dogs partnership.

Jolyon, 53, of Farnham in Surrey, had been a distinguished finance lawyer for almost 30 years and was working and living in Hong Kong when he was struck down with a type of throat cancer.

Although the cancer was successfully treated, he developed paraneoplastic cerebellar degeneration, a rare condition that affects less than one per cent of cancer patients.

It happens when the immune system releases antibodies to destroy the tumour. But while trying to get rid of the cancer, the antibodies accidentally damage healthy cells too.

In Jolyon’s case, they attacked the cerebellum, the part of the brain that controls movement, balance, cognitive and speech skills.

“I lost the ability to walk within a week,” said dad-of-three Jolyon. “It was very rapid and there was a slow decline for a period of time.”

Before his illness four years ago, Jolyon had a successful career as well as being a keen golfer who also played squash and tennis.

Today he enjoys disabled sailing with Sailability, with Odin, who turns three in July, waiting on the jetty. The dog was even on stage when Jolyon collected an award in the sport last year.

The family took Odin on as a puppy, and soon knew he was capable of going on to achieve great feats.

“We’d had this breed before so we knew what they were like,” said Jen, a 46-year-old corporate lawyer who gave up her career to care for her husband.

“We got Odin at the end of Jolyon’s cancer treatment and the kids had moved school. Having him was a distraction for the family.

“He’s a great family dog and was a very active puppy and the vet said ‘he needs a job’.

“As he is clever and intelligent, we had it in the back of our minds that he could be an assistance dog.

“Once he matured, we researched a number of charities and Support Dogs matched what we were looking for – we were looking at our pet dog, who is very much part of our family, being an assistance dog; a dual role.”

Jolyon said: “It’s fantastic to have graduated as a Support Dogs partnership. It gives us both reassurance that extra help is there.”

Jen added: “That Odin is able to help Jolyon is extra peace of mind.”

Support Dogs trains and provides specialist assistance dogs to help autistic children, as well as those living with epilepsy or a physical disability, to live safer, more independent lives.

The charity receives no government funding and relies entirely on voluntary donations.

To find out more about the work of Support Dogs, visit www.supportdogs.org.uk or call 0114 261 7800.