Chemistry professor and forensics expert Susan Parry explains how her second novel was delayed after she was struck down with a debilitating illness which paralysed her from the neck down. She tells Julia Breen about her fight back from the rare condition

THE doctor's orders were to stay in bed and Susan Parry reluctantly listened.

She'd been suffering from a mysterious virus for a week and was thoroughly fed up, not the type to take to her bed at the hint of an illness.

"I was feeling really, really rough," she says. "I was in bed, but got up to go to the bathroom - and my legs just collapsed.

Within 24 hours, all feeling had gone from the neck down."

Susan, a professor of analytical chemistry at Imperial College London, had been on a high; her first novel, Corpse Way, had been published a few weeks before.

Now she found herself lying on the floor of her Surrey home, unable to get up.

She eventually managed to drag herself back into bed. "I was strangely calm," she says. "I thought my husband will be home in a few hours, I will ask him what is wrong', and I just lay there, waiting for him to come back."

Susan was admitted to hospital straight away by a sharp-eyed doctor, who suspected what was wrong and wrote on her notes: "Possible Guillain Barre Syndrome". She was diagnosed with the auto-immune disease - which she describes as being like MS but reversible - and spent six months in hospital.

The first seven weeks were spent in intensive care on a ventilator as her lungs were affected.

SLOWLY, after being given doses of immunoglobulin, weeks later she began to regain some movement in her arms. "It was a long haul then,"

she says. "I had to learn to walk again. I had no strength at all as my muscles had completely gone and I was in a rehab unit in a little cottage hospital for six months."

The slow process of learning to walk, brush her teeth, even use a knife and fork again, had begun. Once Susan was able to move into a wheelchair, the intensive physiotherapy started.

"It was just like in a Hollywood film,"

she says. "They hauled me up to these bars and I had to walk along them. They would ask me to climb two steps, and I would only manage one, and they said that was great. But I was so confused because I felt I'd failed and I should have been able to climb two."

Susan wasn't even able to work on her novels while she was ill. "I couldn't even hold a book and listening to music was difficult. For a long time I wasn't able to do very much. I became totally institutionalised,"

she says.

"I even had to learn how to use a knife and fork again, like a baby, because the grip wasn't there. It was a problem in the connection between the brain and the limbs."

It would be another year before Susan was able to visit her beloved second home, a farmhouse in Swaledale, as she was unable to climb stairs or walk on uneven ground.

When she left the rehab unit in March 2006 she could walk with two sticks and her recovery since then has been remarkable, helped by one-to-one Pilates classes, which built up her strength.

The only evidence of the disease is a small lack of feeling in her toes and she is now able to walk seven or eight miles in the Yorkshire Dales again.

She says: "At first balance was a problem and it was hard to walk in uneven fields. It feels like very hard work, but that's because your brain is having to work so hard."

Susan has just published her second novel, Death Cart, which, like her first, is based in the Dales. Death Cart follows Millie, a student archaeologist working on a chariot burial in Wensleydale, who finds herself caught up in a modern-day mystery.

"I have always been very interested in crime novels," she says. "It is like compiling a crossword. All the different parts have to tie in and you have to develop elements of surprise. My favourite writers are PD James and Ruth Rendell, but when I'm writing I try not to read crime novels in case I subconsciously pick up the plots."

She writes very scientifically, with a spreadsheet monitoring her aim of writing 500 words a day and another spreadsheet showing timelines and what her characters are doing at different points in the novel.

Her novels also draw on some of the real-life cases she has worked on. Susan is an expert in the field of forensics and environmental science and has done a lot of consultancy work with her colleague, Professor Kim Jarvis.

She worked on the high-profile Chohan case several years ago and her evidence about matching soil samples was part of the case which convicted gangland boss Kenneth Regan and his two accomplices for the brutal murders of the entire Chohan family, including an eight-week-old baby.

Her techniques have also helped authenticate the date of paintings by analysing paint samples, including a work ascribed to Leonardo Da Vinci, entitled the Holy Infants.

Susan's farmhouse in Swaledale is perched on the side of a hill above Low Row, with sheep grazing in a neighbouring paddock. She spends as much time as her busy schedule allows up here and has plans to retire to Swaledale.

Her books have been published through her own publishing company, Viridian, which also publishes her academic texts.

"We set up the company to publish an academic text in paperback and were surprised how straightforward the process was. I then admitted to my colleague that I had written a novel and she said we should publish it," says Susan.

"The local shops were very supportive of the first book and Ottakars had it on a stand as I was a local author, but unfortunately, now they are Waterstones, they are no longer able to do that.

"It would be nice if my books encouraged people to visit the Yorkshire Dales.

Swaledale is beautiful, probably one of the most unspoiled parts of England."

Susan's third novel is based in Ingleton and the Skipton area and is still a work in progress.