George Orwell is probably convulsing in his grave at the Big Brother revelations of Edward Snowden. The idea of being snooped on is horrible and creepy, and has caused widespread revulsion and anger.
So why do so many of us do it ourselves, to our very own boyfriends, girlfriends, husbands, wives?
Be honest now: would you ever snoop on your partner? Have you ever snooped on them in the past? Or have you ever been snooped on yourself? On a scale of one to 10, do you find the idea ethically indefensible, or a necessary pragmatism to make sure nobody is taking you for a ride?
Is it a normal part of modern relationships, or only something you do if you are utterly convinced you are being deceived and need some final proof so that you can exit the relationship with some residual peace of mind?
And once you've sneakily gone through your partner's stuff, what happens then?
First, here are some facts. A 2010 study of 920 couples by Dr Ellen Helsper and Dr Monica Whitty of the London School of Economics – titled 'Netiquette Between Married Couples: Agreement About Acceptable Online Behaviour & Surveillance Between Partners' – revealed the following.
Yes, we snoop, and women are more likely to do so than men. And given that the internet is a vast playground of temptation, instant gratification and effortless connection, our snooping has become more sophisticated, yet more mundane.
Snooping used to be about grainy photographs of people leaving hotels with secret lovers, or checking for unknown lipstick on familiar collars. These days, it's gone digital. In 44pc of couples, at least one partner was secretly monitoring the other's digital private life. One fifth – 20pc – of the sole snoopers were men, while 43pc were women, and 37pc of couples secretly monitored each other.
One tenth of couples secretly read each other's emails, and in 22pc of couples there was a lone email snooper; the same percentage read each other's texts, while one fifth of couples had one partner who routinely read the other partner's texts.
Just 4pc mutually snooped on each other's browsing history, but 16pc of couples had one partner regularly checking the other in secret.
These methods were the most common ways of digitally snooping, but there were others: installing monitoring software, reading the logs of instant messaging and even pretending to be another person online in order to get a partner to cross a fidelity boundary, to 'prove' that they were being unfaithful.
But is it all about fidelity? Apparently yes. The reason for so much digital snooping is, according to the 'Netiquette' study, because most people find transgressive online behaviour unacceptable. The great majority – 90pc – would not be happy if their partner fell in love with someone else online; 84pc would not like if their partner had cybersex; 70pc would disapprove of their partner communicating relationship difficulties to a third party, and 69pc would not like their partner to flirt online.
Within these figures, women were more likely to find these behaviours problematic.
But what about snooping? Isn't that problematic in itself? It's one thing to snoop on your other half to find out if they have been playing away, so that you can confront them, but what if it's just nosiness gone into overdrive? Or do people only ever snoop because they feel strongly suspicious about their spouse's behaviour? Anecdotally, no.
How many times have you casually heard about someone scrolling through the messages on a phone that is not their own? Not exactly uncommon, is it?
Relationship expert Fran Creffield warns against casual prying: "Before you consider snooping, think about what you might find, and if you will be able to handle it. For instance, you could find out that your partner has been talking negatively about you to others.
"If you go looking you might not find evidence of infidelity, but find that, for instance, your partner has been complaining about you to a third party. If our partners heard every conversation we had with our girlfriends, how would they feel?"
In other words, the real Pandora's Box may not be that your chap is sleeping with your best friend, but that he has been moaning about you to his mum. What can you do with this information? Tell him you're furious that he's been bitching about you, and you know that he has because you read his private messages? This hardly leaves you bathed in integrity.
But what if your situation is serious – you have a home, a family, a life together, but although you sense something is amiss, your partner is repeatedly telling you that you're imagining things. What if the signs are more subtle than your partner endlessly showering, regularly deleting their digital history or having a secret second phone?
What if it's just a niggling sixth sense that something is up?
Verity is an infidelity detective. She came to the attention of author Kate Figes when Figes was researching her book 'Our Cheating Hearts: Love & Loyalty, Lust & Lies'. Figes tells us that Verity receives about 100 calls a week from individuals concerned about their partner and what they may be up to.
"With their permission, [Verity's] company can install monitoring software in computers and tracking equipment in cars and conduct visual surveillance, so that suspicious spouses can build up a picture of what their partner might be up to when they are not together," writes Figes.
Yet astonishingly, 70pc-80pc of those monitored by Verity are not having an affair. They really are working late, or out with their pals.
"That can be a bitter pill to swallow, too, accepting that your partner might be happier talking to someone else than to you," she says.
If all those showers simply mean your partner goes to the gym a lot, or their absence from home really is because of an evening class, what do you do with the secret information that you have deliberately gathered?
And even if you did find out that your beloved was behaving less than honourably and you snooped in order to confirm what you already knew to be true, how would this snooping impact on your future relationships?
"If people download often illegal software to retrieve deleted messages, how can they then take the moral high ground?" wonders Creffield. "And imagine your next partner asking you about how you discovered your last partner's infidelity, when you explain how you hacked into their email and read their messages. You take that history into the next relationship."
Obviously, if someone violates what holds a relationship together – trust and intimacy – then snooping seems like a justifiable response. Nobody likes to be made a fool of. And just as some people having an affair want to be found out so that they can leave their current relationship, there are others who have no intention of dismantling their marriages, yet still wish for sexual variety – without first consulting their long-term partner.
"People tell me that they want concrete proof for their own sanity because each time they question their partner they feel they are being lied to or are told that they are paranoid and imagining things," says Verity.
"They don't realise that once you get to the stage that you are even thinking about having to check up on your partner, the trust has gone. Infidelity is not just about sex; it's not telling your partner something, whether that's an affair or another secret part of your life."
Infidelity, Anthony Burgess once said, is the most creative of sins, and in response we have come up with some eye-wateringly creative responses.
For some time now, a semen-detecting spray originating in Japan has been available to buy online from sites with names such as Cheaters Spy Shop. You spray your partner's clothing, refrain from having sex with them for a few days, then spray again with another substance: semen traces come up bright green.
However, while one website assures us that semen on a woman's clothing is 'conclusive proof' that she has been having sex with someone who is not you, the same does not apply to the appearance of semen on male clothing "due to several factors unique to men". Er, right.
Never mind. You can always put a GPS tracker in their car, download spyware on their laptop, electronically eavesdrop on their calls, or have them followed by people like Verity.
You could even set up a honeytrap – that is, pay someone (because yes, such services exist) to lure your partner to infidelity, either online or in the flesh. Then you have definitive proof that he or she was untrustworthy – except so are you, for employing such methods. But snooping isn't as bad as cheating, is it?
We deplore infidelity in relationships, and since the mid-1980s have become increasingly intolerant of anything less than absolute sexual monogamy. A UK survey in 2011 found that 91pc of 18 to 24-year-olds thought infidelity was "mostly or always wrong".
Yet sexual boredom is, says Figes, "now considered unacceptable, the sign of a failing relationship".
But it's not our sex lives which are deteriorating – it's our expectations of what our private lives should look like, which are now somewhere between the 'Kama Sutra' and a Bollywood romantic musical.
In other words, we do not make space for lulls, droughts or temporary disinterest, because we are constantly reminded by online porn, by mainstream movies, by our hyper-sexualised culture, that we should be having it, multi-orgasmically, all the time. While remaining faithful. Yeah right.
David Williams's work is the opposite of Verity's, in that he runs a website which facilitates discreet extramarital liaisons. Such is our sense of entitlement around sex that we now expect "incredible amounts of sex and a huge variety of sexual content, like having a new Louis Vuitton handbag", he says.
Williams has been running his business for almost 20 years, pre-internet. "It was really pushing the limits to say that there was a place for people to have some fun outside a long-term celibate relationship. There was no internet, so we used the postal system and people were incredibly vulnerable to being discovered."
He says the media has since "demystified the notion of playing away".
So it's all normalised now, all this sexual and emotional deceit. People may have secret sex with people who are not their partners, and their partners may then use secret means to find out what's going on.
"The longer it goes on, the more you have to confront your own dishonesty," writes Figes, until "the initial adventure feels like a betrayal of self."
Hence the desperation to get caught. "Sometimes the pressure cooker of deceit and denial within a relationship builds to such an intensity that the only way out is to get caught through some flagrantly stupid act," she adds.
Such as bringing your lover into your marital bed, or leaving a trail of receipts for unexplained gifts. Snoop on me, beseeches the subconscious of the one who is being unfaithful. Find me out so it can all come to a head. So we can all stop pretending.
Or you could maybe avoid all of this emotional headf*ckery, this relational toxicity, the deviousness and cunning and conniving that is a result of both infidelity and snooping, by being honest. By talking. By being open about your feelings. By putting your cards on the table.
Snooping happens when things have gone very wrong. "The moment you start snooping, you put a block on the intimacy," says Creffield. Although by the time you start snooping, the intimacy may already have left the building.
If you need to secretly spy on your other half, it might be time to either sit down and have a serious talk or, more probably, to pack your bags. Because if you are snooping, it's broken.
The Snoop's toolbox
Disclaimer: use of these products may lead to sudden loss of integrity.
Checkmate Fidelity Testing Kit
Detects semen – think Monica Lewinsky's dress. May not work on cheating men, due to their natural, ah, physiology.
Works better to detect female infidelity, as women do not produce semen.
Simple. Yet awful. Popular in Japan. £40 (€47) from Amazon.
Viaguard Any Source DNA Sample Collection Kit
Not just semen, but any bodily fluid that you can surreptitiously swab. And not just to detect infidelity, but you can check out if anyone has been making babies without telling you.
Think Jeremy Kyle. £9.83 (€11.48) from Amazon.
Set your partner up with a honeytrap – this can be anything from incriminating texts to sexual infidelity.
Basically, you pay a stranger to set your partner up. Very, very dubious. Prices vary.
Cheating Spouse? How-To Catch App
App for iPhone or Android. Promises GPS, ability to retrieve deleted messages, check history, listen in on calls, remotely access partner's phone, hack social media accounts.
All in the best ethical taste. £1.23 (€1.44) from Google Play.
Suzanne Harrington's relentlessly candid and utterly compelling memoir, 'The Liberty Tree', is in shops now