When a relationship is collapsing under the weight of mistrust, can reading your partner's mail or having them followed replace an honest, face-to-face discussion? Kate Browne reports on why we're losing faith in each other.

A billboard sits on the grimy wall of an office block among advertisements for beer, Wonderbras and mobile phones. Traffic below roars past in a mess of metal and smog. On the eye-catching poster is a naked couple locked in an embrace. An ad for condoms, sunscreen or safe sex? Think again. The line underneath reads, "Is it just me ... or is there someone else?" The ad is for a company called Surveillance Is Us.

A friend phones to tell me she's getting engaged to her boyfriend. Fabulous news. I ask her how he proposed. "Oh, he hasn't," she replies. "Not yet." When I ask how she knows he's going to, she says bluntly, "I was going through his wallet while he was in the shower and found a receipt for a diamond ring." Did she 'fess up and tell him? "No," she says, sounding guilty. "I just can't help keeping an eye on what he's doing. I wish I didn't but how else can I trust him?"

According to Anne Hollonds, CEO of Relationships Australia (NSW), trust in relationships is fundamental but people are losing faith in it. "Because we can't rely on trust," she says, "we have to look after ourselves and therefore be self-sufficient, financially and emotionally. This has led to a lot of people being in relationships with one foot out the door all the time."

Having that foot out the door can also mean watching your back. Everyone at some stage might have had a niggling doubt about their partner, a reason not to trust them. Some of us may even have been tempted to read a diary, look at a letter or sneak a peek at an e-mail. But what happens when you begin to suspect your beloved is up to no good and you feel you can't trust them at all? According to some, employing a private investigator to check them out is the next logical step.

Private investigators are pushing the message that life's fast and we're all time-poor and increasingly reliant on services to help us get through the day. You pay someone to mind your children, walk your dog and do your shopping. Now you can pay someone to watch your partner.

In Australia, while it's illegal to tape conversations or tap phones, visual surveillance is legal. Also, visual evidence of an action or event can be procured if it occurred in the public domain. That is, anything that happens in public can be filmed whether the subject of the filming is aware of it or not. Therefore, for the right price, you can have anyone followed and filmed while they go about their day unaware.

Private investigators have always had a somewhat dodgy reputation and a quick flip through the Yellow Pages doesn't do much to help the cause. Most of the ads include cheesy visual cliches - photos of cowboy hats and sheriff's badges, men in trench coats with big cameras peeping through venetian blinds and cartoons of shirt collars smudged with lipstick.

With that in mind, it's a surprise to meet Matt Johnston and Daniel Parr, the owners and directors of Surveillance Is Us. The pair look more like clean-cut young real estate agents. Dressed in suits and brandishing business cards, they are well-spoken and businesslike. "People now view investigators as professionals," says Johnston. "With the old Family Law Act, there was a bit of a stigma attached to being a PI as they were the person hiding behind doors, leaping out and taking photos of people copulating so you had evidence to get a divorce. Now it's acceptable for people to use us. You can have your own lawyer, an accountant and now your own investigator."

Walking into SIU's modern city office in Sydney, there's no sign of a venetian blind or trench coat. The businesses that share the building are architects, lawyers and accountants. At reception, a huge blue-and-green sign proclaims Surveillance Is Us. A corporate-looking blonde offers me coffee before leading me into the boardroom. The bland beige walls and generic office furniture don't have the look of a place that feeds on tragic tales of trust and betrayal. It feels very businesslike, and this, according to the guys who run the show, is the whole idea.

"The greatest difference between us and our competitors is that we specialise in domestic relationship investigation," says Johnston. "We're also very mindful that a relationship break-up is deemed to be the second most traumatic event in a person's life other than the death of a close friend or relative.

"We work with relationship counsellors and family lawyers. We don't just supply videotapes to our customers and then say where's our cheque? If people need it, we have a full range of back-up services," he says.

Thanks to an aggressive and provocative marketing campaign that's seen SIU advertised everywhere from the gay street press to mainstream radio to drink coasters in bars, business has been building since it opened last year. So far, the feedback from the public has been positive. Parr says he likes to compare the growing acceptance of surveillance to that of pre-nuptial agreements. "It used to be the case that if you wanted a pre-nup, people thought there was no point getting married in the first place. These days, it's considered completely reasonable and practical. In fact, you're stupid if you don't. People are starting to feel that way about using private investigators."

The pair say the media is another key factor. "There's been

a hell of a lot of infidelity on TV lately," says Parr. "From

Big Brother to Temptation Island, everyone's seeing what people are really like. We probably always suspected what went on but now it's in the open. People realise that it could happen to them, too."

Steve Murray, the fast-talking owner of Melbourne's Toorak Detective Agency, agrees that television and media coverage of infidelity in relationships helps his business. "It's all linked to stimulation, so when there's something on the telly or in the paper, my phone doesn't stop ringing for weeks."

Murray says he is one of the only agencies in Melbourne that specialises in what he calls "private work". He believes that although this can be a lot more demanding than other lines of business, such as insurance and corporate jobs, it is often the most satisfying. It's also the most exciting, he admits. "I love it. I like solving people's problems. It constantly amazes me how devious people can be. One guy I was following had two wives."

Anne Hollonds has also noticed the trend towards spousal surveillance. "I recently had a call from an investigator who was doing research," she says. "He wanted to understand the psychological and sociological underpinnings of infidelity to enhance his work. I thought, 'Wow, this business must really be booming.'"

According to Hollonds, part of the reason people have failing trust in their relationships is that there's real encouragement to build careers and material wealth instead of their relationships. "Look at what we spend all our time doing," she says. "Look at how we invest our emotional time ... our finances are where we concentrate all our efforts." Yet in a survey by Relationships Australia last year, 94 per cent of those interviewed said the most important thing in their lives was a good relationship - three times more than those who said financial security was most important. So, while our hearts may be in right place, it seems our priorities are totally out of whack.

A basic surveillance service can cost anywhere between $500 and $1,500, plus expenses. So why do so many people bother? "For most, it's all about peace of mind," says David King, owner with his partner, Mary Kowalski, of Sydney's Lipstick Investigations. "I also think a lot of people do it so they can say, 'Ha, ha, I've caught the bastard.'" A private investigator for more than 10 years, King runs Lipstick from home. Walking into the couple's sumptuous apartment, it's obvious people's paranoia pays - big time. Sitting at an enormous desk framed by a sparkling view of Sydney Harbour, David King mentions he owns a sports car but "obviously I don't use it on the job as it'd be a little obvious".

According to King, business is good. "Lipstick picks up a lot of business and we have every possible kind of client. They are aged from 18 to 70, are equally male and female, and come from every cultural and socio-economic background," he says.

"The only common denominator is that we're usually a last resort for people," says Kowalski.

Many clients will use the evidence King provides to blackmail their partners by threatening to tell friends or family. In some cases, it's the family that gets involved in the first place.

"I had one job where a mother contracted us because

her daughter wouldn't believe her husband was playing around," he says. "Because the mother was actually the client,

I had to rock down to this girl's office and put the video evidence on for her. There she was, with her baby in her arms. Obviously she took the news hard because she didn't want to believe it."

All the investigators admit that having to deal with such personal scenes is tough. Kowalski says she's starting to get used to it. "You really have to distance yourself from your work. But when I see women with kids being cheated on, it's really hard." Earlier in his career, King says, he found the work depressing but he's hardened now. "There's still the odd job that brings a tear to the eye," he admits.

One positive, say the couple, is that they often build up strong relationships with their clients. "Because no-one else knows what's been going on, we act as confidantes," says King. "Some of the people we end up knowing the most personal details about have become our good friends after the job's finished."

Occasionally, admits Johnston, some clients' emotional issues can get out of hand. "We are very aware of the trauma people are going through, but with some you realise you just can't help them. They need counselling instead," he says.

Some clients employ an investigator for practical reasons, not emotional ones. Many have more pressing issues to resolve than a breach of trust. "If you suspect that your partner is seeing a sex worker, you'll have some serious health concerns," says Johnston. "We also had a woman whose husband was seeing another man and that can be a need-to-know situation, too."

For others, just finding out the simple truth is valuable enough. "Susan" (see box on page 12) approached Johnston to have her husband checked out because she suspected he'd been cheating on her. Video proof was enough to end the marriage. Initially hesitant, she agrees to talk over the phone.

Susan feels guilty about using an investigator and hasn't told anyone apart from one close friend. "It's a very personal thing to discuss but I'm sure my story will be like so many other women's," she says. "Other than following him myself, which I couldn't do, there was only one way of finding out if my suspicions were right."

Getting an answer to a specific doubt is one thing, but do some people become addicted to knowing the truth about everything? "I like to use the word addicted a lot," says King. "We had one male client who, after having his mistress checked out, said, 'Great. Can you check out my wife, too?' He knew he was being hypocritical but didn't really care." Kowalski says that once people use their services, they often return - repeatedly. "We actually get customers saying, 'I hoped I wouldn't need you guys again but we got back together and there are still things I'm worried about.' Often, it can become less about wanting to know if someone's having an affair and more about what their day-to-day activities are. It can get quite bizarre."

Gary Bouma, professor of sociology at Monash University, says the role of the private investigator is simply a professionalisation of what has always existed informally. "Surveillance was once limited by the fact you couldn't do anything in Brown Street because Mrs Jones the neighbour would know," Bouma says. "Now we're going to more formal surveillance mechanisms with everything from neighbourhood watch to video cameras everywhere."

Bouma is concerned that things are going too far. "The ethical question is the clash between the rights to privacy and the rights of someone else to know. Privacy is something that needs protection as these more formal mechanisms of surveillance and information sharing become available," he says.

According to Hollonds, you can have too much truth in a relationship. She believes that although honesty is a very important element to building a relationship, there's an equal need for a balance of respect against complete honesty.

"In some circumstances it's more respectful to not tell someone something that's going to hurt them," Hollonds says. "Obviously, you need to be careful that you're not deceiving yourself but sometimes complete honesty isn't always the best way to go."

As for my friend, she called me back to tell me that she was definitely getting married. This time her boyfriend had actually proposed to her. I ask if she'll ever tell her fiance about the wallet incident.

"I do feel guilty; maybe I should tell him," she admits. "But then again I was always the sort of kid who looked at my Christmas presents early. And, really, what he doesn't know won't hurt him."

Susan's story

Susan*, a 40-year-old wife and mother, always imagined life would offer plenty of challenges, but hiring an investigator to follow her husband wasn't one of them. She suspected that her husband had been cheating on her for several years. "Throughout my marriage I thought there was something going on but I had no concrete proof. Every time I confronted him, he'd say, 'You're imagining it; you're obsessed.' But I got to a stage where I knew I wasn't imagining it."

Although she wanted to know the truth, Susan struggled with the idea of putting him under surveillance. "I felt slightly disloyal and that it was an invasion of privacy. I wouldn't want anyone to do it to me, but then I wouldn't be cheating in the first place," she laughs nervously.

After seeing an ad in the paper, Susan tried to call several times but always got scared and hung up. Finally, after another explosive argument with her husband, she plucked up the courage to make an appointment. "It's not normally in my nature to do things like that but I was desperate," she says.

After she provided the investigators with information, her husband was put under surveillance for five weeks. It didn't take long to confirm he was seeing another woman. "I had mixed emotions when I found out. I was extremely upset but

I also felt triumphant in a way. It was hard because I was watching my husband with someone else but it felt good on another level because I'd achieved what I wanted to achieve. Some people said, 'You're going to destroy your marriage because now you know the truth.' But if you don't have that basic trust, how can you carry on anyway?"

Susan waited several months before confronting her husband. "I was dying to blurt it out but I didn't because

I hadn't decided what to do. But knowing gave me more strength. In a way, I almost wanted him to slip up and do something else so I could catch him out. It's crazy, I know."

When Susan finally did tell her husband that she knew he had a lover, she never admitted she'd hired a PI. "I just told him that our marriage had to end because I'd found out everything," she says. "That shocked him."

Now in the process of getting a divorce, Susan says she has no regrets about using an investigator but admits she's upset she didn't sort out her relationship sooner. "I don't think I'll ever allow myself to be in that situation again. But I was so in love, and I was young and naive.

"I didn't want my kids to grow up thinking this was a normal marriage. When I turned 40, I realised I didn't want to be sitting here at 50 in the same situation."

* Not her real name.

How to spot a cheating heart

* Altered daily routine Extended work hours, coming and going to work at different times, taking different routes or means of transport, increased or extended travel.

* In social group or friends Neglecting some previously cultivated friendship and/or pursuing new ones with intensity without apparent justification.

* Changes to grooming New style of clothing or physical appearance or buying new clothes more often; smelling of an unfamiliar fragrance; possessing strange personal gifts or items.

* Spending habits Additional expenses that are not always justified showing up on receipts or credit-card statements; money disappearing from

bank account.

* Phone calls Increased incoming phone calls that are ended when answered or increased wrong number calls; moving to a different room when receiving or making phone calls. These calls may happen at unusual times such as in the middle of dinner, at a party or late at night. Unusual excuses for leaving social or family activities to attend to "urgent" matters.

* Secrecy around personal life Returning home and immediately going to the bathroom to "freshen up" before any intimate greeting such as a kiss or hug.

* Decreased interest in family/relationship life

* Changes in mood or character Often occurs after a phone call or before going out alone, may be shown in nervousness, uneasiness or aggressiveness. When questioned about an issue related to changes in habit, schedule or phone calls, the explanation may contain inconsistencies. Spending less time in one-to-one meaningful discussions with partner.