Last Thursday night, Laura Price was getting ready for bed when she decided to check on the whereabouts of the rest of her family.

Her son Owen, 14, was safely tucked up in his room, daughter Brianna, 18, was driving home from her friend’s house, while husband Glynne, 46, who was on his way back from a late shift at work, was enjoying a pint with friends at their local pub.

Laura didn’t have to make any calls, send text messages or move an inch to establish the exact locations of her nearest and dearest. She can do it with the touch of a finger, via a mobile phone app which tracks their every movement and shows where they are on a map.

‘Glynne had told me he was coming straight home, so I sent him a message saying: “What are you doing in the pub?” He came home sharpish afterwards,’ says Laura, wryly.

Eric Martin, 56, was unaware his wife, Thanaa (pictured, with their children) knew his every movement until one day last year when he lost his phone. Unbeknown to any of her family, she had set up ‘family sharing’ on hers, his and their children’s phones, accepting requests sent by her to them, so she could use Find My iPhone to locate them

‘I worry when Brianna is driving at night, as she only passed her test in May, so I plotted her progress along the roads on the little map that comes up on my screen until I could see she’d arrived safely home.’

While once the preserve of paranoid lovers — and stalkers — tracking equipment is now available on most modern handsets, thanks to huge advances in mobile phone technology in recent years.

And who are the most enthusiastic devotees of this tracking technology? Eagle-eyed middle-class mothers, keen to keep track of their broods — and their husbands.

When Laura, a 46-year-old charity support manager from Newport Pagnell, Buckinghamshire, downloaded the free Find My Friends app, which is just for iPhones, onto her handset three years ago, it allowed her to monitor her children’s every move.

Not that she told them that, of course. While they were sleeping, she opened the Find My Friends app on her phone, added the two of them from her list of contacts, and, when the tracking request popped up on their phones, she accepted it on their behalf, leaving them none the wiser.

The tracking app is very simple, and works with the help of GPS signals more commonly used to operate Sat Navs in cars. When you tap on the name of a person you are following, a circle, bearing their initials, pops up on a map on your screen, pinpointing their location.

If you’re struggling to picture it, it’s exactly like the Marauder’s Map from Harry Potter, which showed the movements of everyone at Hogwarts. Except now it’s not fantasy and can plot the whereabouts of your family anywhere in the country or, indeed, the world.

When Laura caught her son going somewhere he shouldn’t, such as too close to the local river, she would call him and order him to go somewhere safer.

Understandable, you might think, to want to keep tabs on a young boy. Yet Laura also tracks the movements of her adult daughter and her husband.

Around three-quarters of people in the UK now own a smartphone, all of which have the ability to keep tabs on others via various apps

Laura believes she’s right to track Brianna when she goes out in her car, because of her limited driving experience, while knowing exactly when to expect her husband home from work enables her to plan dinner.

However, she admits to using the app for other purposes, too.

‘Glynne took our daughter to the dentist last week, and when I checked my phone she was still there in the surgery, while he was in a nearby pub,’ she says.

‘I sent him a text message saying: “Why are you in the pub and not with Brianna?”

‘When I told him I was stalking him on the app, he sent one back saying: “Damn, you caught me out!”

‘Thankfully, my husband going to the pub is not a source of arguments. He might be less willing to have the app if it was.’

While Glynne feels confident that Laura will never find him doing anything more incriminating than having a cheeky pint, the same may not be true of more suspicious spouses who use the technology to check the whereabouts of their other halves.

In fact, the Prices’ whole approach to tracking one another is all very light-hearted, and Glynne concedes he has no issue with Laura knowing his whereabouts.

‘Sometimes I do think I can’t do anything without my wife finding out!’ says Glynne. ‘But in all honestly I don’t mind.

‘It means she never risks calling me when I’m driving, and I, too, like knowing that the kids have arrived somewhere safely.’

Brianna, on the other hand, isn’t always quite so amenable.

‘There have been occasions when she’s stormed out of the house in a strop and turned the app off. I know because a message pings on my phone telling me.

‘But I’ll text her and say: “Put it back on. Fair enough you want a bit of time on your own, but at least let us know where you are”,’ says Laura. ‘And she always does, because she knows it’s for her own safety.

While permitting her parents to follow her in this way, Brianna has kept the app secret from her friends. ‘It’s embarrassing,’ she says. ‘My friends would think it was a bit clingy of Mum and Dad.’

However, she admits: ‘There are times when I turn it off, but I can also see the benefits of my parents always knowing where I am.

Tracking apps are exactly like the Marauder’s Map from Harry Potter, which showed the movements of everyone at Hogwarts. Except now it’s not fantasy and can plot the whereabouts of your family anywhere in the country or, indeed, the world

‘It makes me feel safer when I’m driving because Dad could, for instance, find me and change my flat tyre if I needed him to.’

And, of course, the tracking app works both ways, enabling Brianna to check her parents’ whereabouts too. Thus, she knows exactly when they will be home, and can be confident when she has friends over that they won’t be disturbed unexpectedly.

Brianna isn’t the only teenager who is willing to let her parents keep constant tabs on her. Indeed, many teenagers agree to being tracked in return for later curfews and more freedom — albeit under survelliance.

Two years ago, Owen found an unexpected upside to his protective mother tracking his every move, when he collapsed while playing football with friends and she used the app to trace him to a local park.

One of Owen’s pals had called Laura to say he was unwell, and when he struggled to describe their precise whereabouts, she used her phone and the icon for her son to find him.

‘I rushed to the park and, when I saw the state he was in, called an ambulance and he was taken to hospital,’ recalls Laura.

Dr Annie Hinchliff, a chartered psychologist, can see why parents would be concerned enough about the whereabouts of young children, newly navigating the world, to use the technology, but says that monitoring one another’s every move could be a step too far.

‘Parents are a lot more controlling now than previous generations, which means children have less freedom to take healthy risks and make their own mistakes,’ says Dr Hinchliff. ‘But, still, it’s understandable that mothers and fathers will want to do what they can to keep their children safe.

‘Tracking partners or parents, however, is different, because everyone involved is an adult, with freedom to come and go as they choose.’

Many men would be furious to discover that their wife was covertly tracking their whereabouts.

Fifty-six-year-old maintenance supervisor Eric Martin was unaware that his wife, Thanaa, knew his every movement until one day last year when he lost his phone.

Unbeknown to any of her family, she had set up ‘family sharing’ on hers, his and their children’s phones, accepting requests sent by her to them, so she could use Find My iPhone to locate them.

I work full-time and knowing I can keep tabs on where everyone is while I’m there makes me less anxious Mother of four, Thanaa Martin

In fact, some mothers are able to track their families without even doing this, because if a family uses the same icloud address, which is common, they can simply use the app that helps you track the family’s devices — and the person who is carrying them.

‘I asked Thanaa if she would dial my number, so it would ring and I could search for it. But she said: “There’s no need. I can look on my phone and tell you exactly where it is,” ’ recalls Eric.

‘She told me she has a facility on her mobile which means she always knows where the children and I are, as long as we have our phones with us.

‘I couldn’t believe it. I had no idea such a thing even existed.’

Thanaa’s behaviour does seem rather cloak and dagger, or, at the very least, over-bearing.

So was Eric cross with his wife, who works as a nurse in A&E, for spying on him for several months without letting on?

‘I was surprised that she hadn’t mentioned it, but I’ve nothing to hide,’ says Eric.

‘I know she probably worries more than most because of her job. She treats people who have been in some terrible accidents, which could well make her think we’re at greater risk than we are.’

Thanaa, 40, who lives in a village near Chigwell, Essex, with Eric and their four children, Noor, 15, Samaa, 14, Joseph, 11, and Zara, four, uses the Find My Phone and Find Nearby Friends applications to keep tabs on the whole family.

‘I do worry about my family because the world is getting scarier,’ says Thanaa. ‘Also, my husband drives a lot for work and the roads can be very dangerous.

‘The app means I can see when he’s heading home and try to have dinner ready. Or check that he’s collected the children on time from their horse riding and music lessons.

‘I work full-time and knowing I can keep tabs on where everyone is while I’m there makes me less anxious.’

But being able to surreptitiously spy on her family means that Thanaa has caught most of them out getting up to things behind her back.

Last year, Samaa was grounded for a week for taking a trip with friends to Westfield shopping centre in Stratford, East London, 40 minutes from home by train, after telling her mum she was going into the local town.

Likewise, Joseph wasn’t allowed to play out for a week after Thanaa detected him, through her app, half a mile from home when he was supposed to be off school sick. She was at work, and he had been at home with the nanny but sneaked out for a game of football.

Eric, meanwhile, was in the dog house last year after Thanaa spotted him doing some very last-minute shopping, two days before Christmas, in a nearby gift shop.

‘Although I wish he was more organised, all was forgiven on Christmas Day when I discovered he’d bought me my favourite perfume and a gift voucher for a massage,’ says Thanaa.

And, as far as Thanaa is concerned, living without an air of mystery is a price very much worth paying for the peace of mind she gains from being able to track her family.

‘Yes, this technology does feel like a step up from everyone being constantly contactable via their mobile phones,’ she says. ‘We’ll probably, God forbid, all be micro-chipped in another few years.’

Around three-quarters of people in the UK now own a smartphone, all of which have the ability to keep tabs on others via various apps. While there are no official figures as to how many of these apps have been downloaded, parenting website Netmums says their use is growing fast.

Debby Penton’s husband, Mark, cycles 12 miles each way to work and back, and she uses the Family Map app to re-assure her that he’s not lying face-down in a ditch.

The couple, from Kingston, Surrey, downloaded the app to their phones earlier this year, just before their eldest son, Ben, started secondary school.

Like many parents, they worried about 11-year-old Ben making his own way there and back on the bus, after years of being chauffeured to and from primary school, but being able to check on each other’s whereabouts was an added bonus.

Debby, who runs her own PR company, had worried for years about Mark, a planning consultant, cycling, so set up an alert via the app which pings when he leaves work and then again when he turns into their street.

Mark, in turn, can track his wife on his phone and will sometimes remark casually, over dinner, that he has seen she called into a particular café or shop during her lunch break.

‘If I was up to no good I might be worried, but we have a strong relationship so the fact my wife always knows where I am doesn’t concern me at all,’ says Mark.

‘I’ve heard horror stories of people putting phones in boots of cars to try to catch out their loved ones, but our situation is not like that at all.’

Debby, who has a younger son, Luke, nine, who doesn’t yet have a phone, also finds it’s useful for ‘micro-managing’ her family, when she’s at work and Ben is making his way home.

‘One day, after school, Ben wasn’t answering his phone and I began to panic, but I could see where he was on the map on my phone so decided to go and pick him up,’ she says.

‘He was so shocked to see me when I pulled over in the car, and said: “Mum, how did you know I was here?”

Ben himself has some reservations, though. Debby says: ‘He’s told me: “I’m not really sure how I feel about you tracking me.” ‘But my answer to that is: “You wouldn’t have a phone if I wasn’t paying for it, so you’ll just have to put up with it.” ’