It may be Braintree rather than Botswana, but unlike bestselling fictional sleuth Precious Ramotswe, Jo Clarke and Jo Nixon are the real deal. They are the founders of Britain’s very own No.1 Ladies’ Detective Agency. Just two years old, the phones at D-Tec UK are hot with calls from those who want to keep tabs on wayward wives, philandering husbands or troublesome teens. Not forgetting businesses with offices to bug, or debug, and those in need of some executive security protection.

As befits a private investigation service run by women, there is no sign of the trench coats or nicotine fingers associated with the male-dominated world of the PI. Both its founders, in their forties, are blonde, businesslike and very neatly turned out. No dirty tea mugs for them; these sleuths have a cappuccino machine.

Most PIs are either ex-police or Armed Forces. Clarke and Nixon are neither, although Jo Clarke harboured a teenage dream to join Interpol, and once did work experience with Essex Police. Prior to setting up D-Tec, she ran a language school. She is also a life coach and a hypnotherapist with a calm voice and an understanding smile. Jo Nixon had run various businesses, including a cleaning company.

“This line of work can be round-the-clock, so it helps that we are friends,” says Clarke, who has just dispatched a tail to follow three married women on a girls-only weekend to Dublin. One of the husbands is suspicious of his spouse of 20 years. Clarke expects to spend most of the weekend conveying “behavioural reports” to her nervous client.

“It started as a mums-at-the-school-gates thing,” Nixon chips in. “Our daughters, now 12, have been at the same school since they were 5. We both had our own businesses, but we sort of migrated towards each other.”

What led them to branch out, together, into an alien world of surveillance and sleuthing can be summed up in one word: divorce.

Both their marriages broke up at the same time. In the last throes of hers, Nixon found her husband removing something from underneath her car. “It was a tracker. He was convinced I was having an affair, which I wasn’t… But I don’t want to go into that,” she adds quickly. “Have you seen a tracker?”

I confess that I have not. Or not as far as I know. “I’ll show you one,” she says, and produces a metal box a little bigger than a cigarette packet. “A tracker can be deployed magnetically anywhere on a vehicle, usually underneath, and it works via a GPS. Come and see the other end of things.” She logs on to one that is currently deployed. A map comes up on screen with a series of balloon shapes that are plotting a journey. “We’ve been following this man’s progress along the M62 around Manchester. He is parked up at the moment. I can play back his journey, see exactly where he has been and what speed he was travelling.” His wife, back at home in York with their baby, has called D-Tec because, after an almighty row, she is convinced her husband is having an affair. “OK, let’s zoom in,” Nixon says, warming to the task. Thanks to Google Earth, she can focus down to the building where the man is parked. It is not the hotel he has told his wife he is staying in while away on business.

“It’s his secretary’s house,” Nixon reveals. “That’s where he’s been since the first night away. There’s no hiding from a tracker. He’s absolutely no wriggle room,” she says, using one of her favourite expressions. “I find it incredibly sad that so many men have this midlife crisis after the birth of a child and go off and have an affair,” she reflects.

Will this client now proceed to divorce? “It is not our job to judge or give advice,” Clarke smiles. “All we do is produce a factual report,” adds Nixon. “We don’t offer advice unless we are asked.”

They may be divorcées, but these are not women on some anti-men revenge mission, though Nixon admits her ex-husband’s tracking of her was the seed of their business idea – and that the bulk of D-Tec’s work, like most other agencies’, is matrimonial.

“For many women, the idea of going to a private detective agency is terrifying,” says Clarke. But that’s precisely what’s now happening in increasing numbers. “Many more women are earning and leading their own professional lives, and they just want peace of mind if their partners start behaving strangely – such as spending a lot of time on their mobile in the bathroom,” Nixon continues. “We also do a lot of prenuptial work. If a woman is marrying a man who has gone through a couple of divorces, she will ask us to check that he is the company director he says he is, rather than an undischarged bankrupt.”

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