"In another world I wouldn't have gone into medicine but my dad was a doctor and I gravitated towards that," says medic turned children's author Professor Anthony Kessel.

The former Public Health England director had negotiated part time hours to focus on his writing when the pandemic struck.

"It was a big life change for me to make space for something else, but then they asked me to come back full time," says the Crouch End author.

Working at NHS headquarters, he was responsible for national clinical policy, bringing experts together to decide who got which drugs for Covid - based on the research available.

"It has been intense and quite demanding." he admits.

As PHE's former global health director, surely Covid wasn't a surprise?

"Yes and no, I traveled the world extensively to rich and poor countries, there was Ebola and other outbreaks and I played a senior role in the swine flu pandemic which looks less significant now, but as a lead national director I was on the 10 O'Clock news. Of course we knew something like this could happen, but when it does, you are still taken aback. I think the NHS has done an incredible job. People have been absolutely dedicated about supporting the country."

He's now back part time and cheering on long term colleague Chris Whitty from the sidelines.

"It's not for everybody but you get used to working with politicians in government. As well as the pressures there's the ability to make a real difference."

Kessel has always loved reading and writing and had written several academic books on medical ethics and the history of medicine when a decade ago he turned his Friday night bedtime stories to his daughter into a self-published book.

"When I published The Amazing Adventures of Perch the Cat, I realised how much I loved creative writing and found it pleasurable, peaceful and fulfilling, so I carried on."

Now, with the encouragement of crime writer Ruth Rendell, he has dusted off a caper he began many years ago about a girl following a trail of puzzles from her dead mother.

The first of a four-book teen mystery, The Five Clues (Crown House Publishing) follows 13-year-old Edie as she solves the mystery of her mum's death - against the backdrop of a pharmaceutical company concealing development of a lethal virus.

"I had written the first few chapters and left it on my shelf. Ruth read them and was a great inspiration. I asked for tips on crime fiction but she said 'you don't need it, you are doing the right things already.' It was a huge boon."

Edie is inspired by Kessel's "extraordinary super special" 20-year-old daughter Leone.

"We have always had a very close relationship. We did the cat book together, she did the illustrations. She has written poetry and a novel already. Like Edie she is very determined."

The book starts with Edie finding a note from her mother - a detail Kessel wrote prior to his own mother's death in 2010.

"It was very sudden, she had a haemorrhage and died overnight. In the weeks afterwards we searched the house for her will and her money and found them concealed in a cupboard in my sister's old room. I opened the box and found a note from mum to me and my sisters. I had written a story about a child who a year after her mother's apparently accidental death finds a note from her mum, and the same thing happened in my life."

A human rights investigator, Edie's mum lays clues to help her complete her investigation, and bring the criminals to justice. It's a race-against-time adventure, but also a story of a young person learning to cope with stressful situations and the loss of a parent via the 'Three Principles'.

"It's hopefully a thrilling adventure story but also a book about grief, hope and someone reaching her potential," says Kessel. "I have seen with my owns eyes the unbelievable benefit for children of focusing on psychological health and wellbeing to cope with anxiety and depression."

Aimed at ages 11 up, it's set around Crouch End and Highgate where Edie attends 'Highgate Hill school' - modelled on Kessel's alma mater Highgate School. The next three books, set three months apart, involve mysteries surrounding terrorism, the environment and dog theft under the umbrella title Don't Doubt The Rainbow.

And Kessel hopes readers will "keep the faith" throughout the series.

Ham & High: The Five Clues is published by Crown House Publishing price £6.99.The Five Clues is published by Crown House Publishing price £6.99. (Image: Courtesy Crown House Publishing)