As a young journalist and writer making a name for himself life was good for Ian Probert. His first novel, Internet Spy, was an early millennial bestseller in America and as his follow-ups began to accumulate a following, he was just about to become a father.

The only problem was that unbeknownst to anyone, he was slowly dying.

The symptoms first began in 1989 when, in his mid-twenties, Probert started to develop a limp. It wasn’t for another 15 years until he was diagnosed with an underactive thyroid, which by this point had rendered him bedridden, bloated and prone to blackouts.

“If you say, ‘I’ve got this symptom, this other symptom and this one,’ in the same go, then it’s easier to diagnose,” the 51-year-old says.

“The problem was that my symptoms developed over a number of years, and as they started when I was young and going out every night, it initially felt like I just needed to rest and take care of my body a bit more.”

The thyroid is a gland in the throat that produces essential hormones of which Probert later discovered he had a deficiency of.

He explains how when it fails to work properly, the results are akin to a car trying to run without petrol and oil. His body was rusting and no one could understand why.

“My GP has a habit of joking about how close I was to death. You see adverts on the television about strokes and plenty of diseases, but I’m really surprised there are no adverts about this saying, ‘Be careful, you can die from it’.

“Your standard GP is fairly ignorant of the condition. I’ve seen a lot of doctors and think that with the research I’ve done on my own, I probably know more about it than them. It was only when, about 18 months ago, a friend casually asked: ‘Have you had your thyroid checked?’ that I even thought about it.”

Having made a full recovery, Probert is working his way back – professionally and personally.

His previous incapacitation made it hard to spend time with his daughter, Sofia, but now she has proved the perfect test subject for his new children’s book.

Johnny Nothing is a story that many may well have dreamt about as children. As the poorest boy in school, Johnny is thrilled when he inherits £1million.

Yet when his evil mother steals the money to go on a spending spree, he forms a plan to imprison his parents, make them do homework and go to bed early.

“One of the first things I did was to read it to Sofia to judge her reaction and hear how it sounds.

“My routine was based around her, so I’d drop her off at school and then write from 9.30am to 2pm non-stop. It can be tempting to lose discipline and sit around watching Jeremy Kyle, but as you might imagine, I was keen to make up for lost time.”

Johnny Nothing is available on Amazon’s Kindle store for £2.56.