Close-up of a man in a suit using a smartphone outdoors.

Have you ever secretly taken a stranger's photo? Here's where you stand legally

We've probably all been in this position; you're on the train, spot someone out of your eye, and instinctively reach for your mobile phone to use as a spy camera. Maybe they look EXACTLY like your mate, and you need to show him his doppelgänger. Or maybe they haven't realised it, but they've got odd shoes on, and you need to let your Facebook pals in on the lols. But have you ever considered the ethical and legal implications of taking a person's photograph without their consent?

In our guide to UK surveillance law, we explain how to stay on the right side of the thin blue line when using spy cameras and outdoor security cameras. Many of the same laws apply to taking a photo with your mobile. For example, if someone reasonably expects privacy, it could be illegal to snap them, no matter what they're doing. However, if their actions extend to criminality, the law changes. And a lot of candid mobile phone snaps that go viral are of exactly that.

1 in 4 Britons have secretly taken a stranger's photo and shared it online

According to research conducted by Online Spy Shop earlier this month 25% of Britons say they've taken a strangers photo without consent and later shared it online. Our research suggests that while secret snappers may think their actions go unnoticed, 30% of us have spotted someone taking our picture or suspected someone of doing so. Our study also found:

  • * You're most likely to be secretly snapped while on public transport.
  • * Young people are most likely to take a photograph of a stranger and share it; 39% of 18-24 year-olds admitted doing so.
  • * Most people share photos via social media, with Twitter being among the most popular platforms.
  • * 90% of Britons think it's OK to take a secret photo if its to record criminal or antisocial behaviour.
  • * 9% say it's always OK to share images of strangers.

Ever thought of snapping a stranger using your phone as a Spy Camera?

Follow our handy guide to see where you stand legally...

Using your Camera Phone as a Spy Camera

Where are you most likely to be snapped by someone using their phone as a Spy Camera?

39% of those who admitted sharing their photos of strangers said they captured the images on public transport. While public transport may be the most tempting place to take a strangers photo, it's also where you're most likely to get caught. 58% of those who believe they've been snapped say it happened on public transport. 26% say they've snapped a stranger in the street, and 20% say they've done it in a restaurant or bar. Other places people admit taking a photo of a stranger before sharing include hairdressers, gyms and university campuses.

How is your picture most likely to be shared?

The majority (75%) of sharing was done via social media, with an almost even split between private social media platforms like WhatsApp and Snapchat (48%) and public social media platforms like Facebook and Twitter (52%). 10% of those who shared images online say they posted them to blog platforms such as Tumblr, and 15% shared them by email.

Feelings around being snapped

On average, 22% of Britons said they had some anxiety about being snapped without their permission. However, this figure was significantly higher among younger adults. 41% of those aged 18-34, typically referred to as Millennials, say they're fearful that a stranger will take their picture. That's almost double the national average.

Attitudes to sharing pictures of strangers

90% of Britons think taking a secret photo to record criminal or antisocial behaviour is OK. But just 9% say it's always OK to share images of strangers. Of the 30% who saw or suspected someone of taking their picture, only 20% say they confronted the person.

Steve Roberts of Online Spy Shop recommends caution regarding covert snaps of strangers. There are many ways to protect your cyber privacy, but unfortunately, there's not much you can do to prevent someone from snapping your pic. And in most cases, it's not against the law to photograph a person in public, assuming they don't have a reasonable expectation of privacy, and your actions don't harass, alarm, or distress them. However, what happens to the photo after it's taken could have wider implications.

Scammers use images of strangers to set up fake dating and social media profiles, often to dupe people into thinking they're interacting with someone else. Then there's the issue of online harassment, which can happen if a picture goes viral and the subject is identified. My advice to anyone concerned about their picture being taken in public is to calmly explain to the person doing it that they dont want their photograph taken and to ask that it be deleted, provided it's safe to confront the person.

"It happened to me!"

Stewart Mathers, an actor and model from Manchester, has experienced secret snappers more than once.

"I think this has happened to me twice. The first time I thought I was being paranoid, so I ignored it. Then, last summer, a woman indiscreetly took a photograph of me on her phone while I was on the tram. I pondered whether I should say something, but she beat me to it and apologised. She said I looked like someone she'd seen in a film but couldn't remember his name. She was more embarrassed than me. I can imagine it would be upsetting for people to have their pictures taken without consent."

"I certainly wouldn't do it to someone; you never know what kind of day they're having or how it will make them feel if they spot you. Having my picture taken didn't upset me at the time, but since it happened, I've had my Facebook pictures used to create a fake profile, so now I'm a bit edgier when it comes to pictures of strangers and me."