I’d struggle to sleep at night if I were Linda Davies. In 2005, suspected of spying on Iran, she was held and questioned for 13 days. She’s just written about that. Her other new book warns of a devastating megastorm. For all that, Steven Russell is relieved to meet a happy optimist.

East Anglian Daily Times: Linda Davies in longbow actionLinda Davies in longbow action (Image: Archant)

You can’t keep a lid on strong emotions forever and last week the pressure valve blew for Linda Davies. She was talking to someone, ticking along nicely, and – wham! – up came the suppressed feelings as she relaxed her guard. She burst into tears. “You never know when it’s going to emerge,” she says. “It’s not far below the surface.”

Not surprising. In the autumn of 2005 – less than a year after Linda, husband Rupert Wise and their children had moved to Dubai – their idyllic existence became a nightmare.

The couple and a friend were sailing a catamaran in the Persian Gulf, near a military island, when they were intercepted by two gunboats and taken to Iran for the first of 40-odd interrogations in locations ranging from a dilapidated building to a five-star hotel.

At one point they believed they were being expelled from Iran but found themselves on a flight to Tehran. There, they were taken away in a van. “I was sure we were being driven to our execution,” Linda admitted later. After three days of detention, she was permitted to phone the children – then aged seven, four and just one – “which was unspeakably painful”.

East Anglian Daily Times: Linda Davies's book Ark Storm.Linda Davies's book Ark Storm. (Image: Archant)

Fortunately, their nanny realised something was very wrong and contacted the British embassy. The couple were freed after nearly a fortnight, following behind-the-scenes pressure from London.

Linda revealed later that the experience left her looking over her shoulder in the months afterwards, while daughter Lara developed separation anxiety.

She explained: “I’ve been brought up to believe that through your own force of will and intellect you can chart your own path through life. When I was yanked so dramatically off this path, I became aware of how fine the line is between a comfortable life and a living hell.”

A few years down the line, it all seemed “quite unreal… as if it happened to somebody else”. Linda tried not to dwell on the worst moments.

East Anglian Daily Times: Linda Davies's book Hostage: Kidnapped On The High SeasLinda Davies's book Hostage: Kidnapped On The High Seas (Image: Archant)

Until about 12 months ago she had no intention of writing about this terrifying fortnight. But she had a change of heart, relived the ordeal in her mind, and her new book Hostage: Kidnapped on the High Seas is the result.

She and I last spoke in 2010, when the family was still in Dubai but was laying plans to move to Southwold. They’d been coming to Suffolk for holidays since the children were very small – Hugh, Tom and Lara are now 16, 13 and 10 – and loved the county.

After eight and a half years in the United Arab Emirates they made the move in 2012 – to a purpose-built house with a view of the marshes and a number of eco features, such as ground-sourced heating and a grey water reuse system.

Does she miss the UAE? “Only on a foul February day with driving rain and screaming wind,” she says over mocha-and-hot chocolate in Southwold High Street. “If I were in Dubai, I’d be walking on the beach in my bikini!”

For Linda, another move was but the latest step in a life far from ordinary.

Born near Glasgow, and raised in south Wales, she was the daughter of a Welsh economics professor father and a Danish mother. After the local comprehensive school she read politics, philosophy and economics at Oxford. Then, from the mid 1980s, came seven years as an investment banker.

She’d tried and failed to write a novel – 40-odd potential first pages started and thrown away – before inspiration came one afternoon in 1991. Angry with her boss, she thought about the damage that could be done to a bank through insider trading. It sounded like a plot for a thriller.

After six months of striving to combine work with writing she quit her career. A good move. Nest of Vipers, published in 1994, has sold two million copies across 30 countries and had its film rights optioned by Hollywood.

Linda and Rupert married in 1995 and the following year she brought out Wilderness of Mirrors (the security services, drug smugglers, arms dealers, the diamond industry, stock markets). There was Into the Fire (a derivatives trader suspected of fraud), Something Wild (money and music) and Final Settlement (featuring an endangered heiress).

When we spoke in 2010, she was in the midst of completing her Djinn quintet – a series of fantastical adventures for young readers in which children get involved with the battle between good and evil and overcome the odds.

The series earned the tag of “Dubai’s Harry Potter” from the newspaper Emirates Today.

So: why did she later decide to revive those awful memories and put them out for public consumption?

Last year, in New York, an investigative journalist friend told Linda: “You know, you’re mad not writing about that. It’s an incredible story; you really should tell it.”

Flying back, Linda pondered. “I thought ‘If I were to write this, what would I do?’” She had with her in the plane a John le Carré hardback.

“There were a few blank pages at the front and back, and I filled them. I wrote, basically, a detailed outline for Hostage. It all came back. I went home and said to my husband ‘I’m going to write this book. I’m going to make time.’ Because by now I’d got excited about it.”

Her agent liked the idea and it was decided to publish the book at the same time as her new thriller, Ark Storm.

Not surprisingly, she found the process emotionally demanding. “I thought after all this time I could do it in a matter-of-fact way, but it was incredibly gruelling.”

The only thing that hurts, still, is anything to do with the children, she says – “thinking about how it impacted them and us not being with them, and remembering getting back to them.

“What happened to us” – she and Rupert – “that doesn’t really have any emotional currency any more – again, probably because I boxed it away. If I really went there in my head again...

“Actually, we watched Argo about eight months ago, with the kids as well, and I was pouring with sweat, hyperventilating, watching it.” The film portrays the rescue of six American diplomats from Tehran during the 1979-1981 Iran hostage crisis.

“Hugh was saying ‘Oh Mummy, it can’t have been that bad. Can’t have been that similar.’ I was thinking ‘You don’t know, my darling. You don’t know.’ He was seven, Tom turned five when we were in captivity, and Lara was a year and 10 months – still a baby.”

Compared to today’s hostage-taking and beheadings by Isis, Linda recognises that what happened to the couple “was of a much lesser order of magnitude”, though the flow of tragic news does strike a chord.

“We were being held by the Iranian state – which is responsible for its own atrocities – but not a terrorist organisation. And we were being held by the ‘good’ part of the Iranian state; not the Revolutionary Guard.

“It could have gone wrong at any stage, and I can joke about it subsequently. People they took while we were in captivity they held for 18 months in prison in Tehran. You never know how it’s going to play out.”

On the wider point of jihad and terrorism, Linda says a good friend is currently involved in setting up a de-radicalisation programme in the Emirates.

“They’re very conscious of it. Here, it means multiculturalism’s failed. We have core values in this country – equality being one of them. Not veiling women and telling them to walk behind you. You come here, you need to buy into our moral system and cultural system. Female genital mutilation... we don’t do that here. This is not how we live, what we believe.

“We should have been much more robust, right from the start.

“Going forward, we send out strong messages. We prosecute that (FGM). We go into the schools, if there are these ‘Trojan horses’. We shut down mosques if there are extremists. They should get warnings and the extremists (be) banged up, but if they carry on they should get shut down.

“When you see extremism, you’ve got to tackle it. You must not allow segregation in schools, because that reinforces this sense of isolation and also disempowers women.

“Women – mothers, wives, daughters – can have a very positive role… can influence the men around them. That’s why it’s crucial women are not put in that subjugated role. They’re bulwarks against extremism.”

As well as taking a robust stand about acceptable values, nations need to create jobs. It’s certainly a concern in Saudi Arabia, Linda says. Lots of unemployed young men without women giving them a sense of perspective… “You can do the psychology, as it were. They’re ripe for jihad and being exploited. The social media in Saudi is very pro Isis.”

The key – there, here and elsewhere – is giving people a stake in something good: “it’s job creation, hope, aspiration, belonging to something that has to be bigger than a mini-caliphate they’re trying to build”.

All that said, she’s hopeful about the future of mankind.

“And living in this part of the world, yes, of course, it’s easy to feel optimistic. I wouldn’t feel the same way living in Syria or Iraq. But you’ve got to take what you have.

“My father was an economics professor – very bright – and he went around looking like a tramp: darned shirts, holes in the elbows, but very happy. He went through the Second World War. He grew up the son of an unemployed miner. He had malnutrition as a child. So, for him, just having a nice jam sandwich was bliss.

“That’s one of the benefits of the hostage thing: you realise, actually, it doesn’t take much to make you feel good. I have to remember that and remind myself not to sweat the small stuff.”