Watching the detectives: Confessions of a private eye

Chris Tarrant isn't the only cheating husband to have had an undercover investigator on his trail. Charles Tomlins-Young reveals the trade secrets and tactics of the matrimonial gumshoe

A client phones me up. It's nerve-racking, contacting a private investigator (PI) for the first time. People are naturally reticent, but we have to persuade them to tell us everything that has evolved that has led them to approach us. We discuss why their suspicions have been raised: flurries of text messages at strange times of day are the modern version of lipstick on the collar.

We receive phone calls from men and women from all walks of life. There's no strict definition as to who will contact us because everyone has problems. But it is an expensive business, so most of our clients are wealthy. High-profile businesspeople and celebrities get in touch regularly, because they know they are assured of complete confidentiality. Our hourly rates for surveillance vary because of requirements of the job, how many operatives are used and the skills needed. Rates for a good investigative team can be between £100 and £200 per hour, depending on the team make-up.

Almost half of cases are matrimonial, and for the people who contact us it can be very difficult to broach their problems to a complete stranger. Members of the public may have seen our website, heard about us through friends or associates and found that we are registered with the Association of British Investigators. We will try to offer advice to those who cannot afford the service - but it's very difficult to follow people without training and you're likely to lose them.

Then follows a series of questions on how to find the subject of the inquiry. If someone works in a nine-to-five job we can pick them up at the end of their working day and follow them. We arrive early, check out the road systems and pick them up at their office. We work out the number of entrances and exits to the office, find out whether they drive or whether they are going to get on the Underground. If someone doesn't have a rigid schedule, we sometimes have to follow them from their front door first thing in the morning.

Ideally we work in three-man teams, with motorbikes. Our surveillance is both corporate and private, and varies from people having affairs to business partners who are not going to meetings when they should be. Quite often, we'll be instructed by the client's solicitors rather than themselves.

You have to be incredibly patient with surveillance; watching the side of a house for six or seven hours, and then within two or three seconds there's a kiss on a doorstep and off the person goes. You have to be very diligent and not flinch from your concentration. But we would never conduct surveillance with just one person. In total, we use two dozen operatives, many of whom are ex-Army or ex-police. We have specialists in de-bugging houses and people who are experienced in enduring harsh conditions. One operative disguised himself in a privet hedge for two-and-a-half days when observing an isolated building. Eventually, the police came by and he had to convince them he was not a vagrant. Nothing came of that surveillance in the end, and he was told to go home and get washed.

In another case, we were watching a man in Pimlico in London, who went into a third-floor flat in a block. We told our client, his wife, that we could confirm he had gone into the building, and when she telephoned him he went out onto the balcony to pick up the call. At the same time, our operatives were able to enter the public hallway of the block of flats opposite. They were able to establish that the woman in the same flat as her husband was very scantily clad.

When following people, we use different types of cameras. They are hidden in tie-pins and Filofaxes. We use specially adapted vehicles outside a given address, and we can stay put all day. In London, when you are following people, you need motorbikes. We'll often use a couple of motorbikes and a car, or if a person uses public transport there will be two people in a car and one in a motorbike - so the car passenger can jump out and get on the Tube if necessary.

One of the key things we say to clients when we first speak to them is to ask them whether they have noticed a pattern in their partner's behaviour. We try to persuade them to keep their partner under a tight rein, so they have no opportunity to see the person they are allegedly having an affair with. But to tell them, for example, in advance, "I will be out with my friends on Friday night". This gives their partner carte blanche to see that person that night. This is a tried and tested tactic, which gets the results that they want with a minimum of outlay to them.

The legalities of both listening to and filming people are very strict, and if there is not strict adherence to relevant laws, the evidence may not be admissible in court. But it is amazing how many people having a clandestine meeting in a restaurant choose to sit in a window seat because it is more romantic. At which point it is not difficult for us to film from outside. If we see a client's partner going into a restaurant we'll try to send in an operative to sit on the adjacent table. It's harder to explain away holding hands than kissing, which can be platonic.

Things are not always what they seem. In one case, someone wanted to check out the male prospective partner of a friend before they got engaged. The friend's suspicions were roused because the man seemed to be putting up a pretence of sharing the same social status as his prospective fiancée. So we followed the man for four days, and the most interesting thing he did was drink a few beers in a bar. Then, on the fifth day, he loaded some bags into his car and drove off. We followed him to the airport, expecting him to be meeting a girlfriend, but found him at the check-in desk. We followed him on to the plane to America, by car into Canada, but again, the most dramatic thing he did was to drink a few beers in a bar.

Different clients require a different degree of closure. For some, just catching someone somewhere they shouldn't be is enough. For others, it's simply catching someone with someone they shouldn't be with. Lots of people do not even need to see the surveillance footage, but will just read the log notes. But there are some people who want a lot more. The most you tend to get is people holding hands when walking down the street or having a snog. Large parts of affairs take place behind closed doors.

We do get some repeat customers, who may come back two or three times over a decade. They may want us to do background checks on new partners, or on the same partner several years on, particularly if they have forgiven them for having an affair once. These individuals tend to be very wealthy, or very mistrusting. Some of the most insecure people are people who cheat on their partners themselves. If you are capable of having an affair, you may believe that everyone else shares that capability.

There are a lot of female operatives nowadays, and in many situations people are less suspicious of a woman than a man. If somebody's having an affair, they are often seeing somebody who themselves has a partner. So often both people are slightly suspicious.

We treat every case individually and are going into the unknown every time the phone rings. It is not just married people who contact us - there are people who have been going out with each other, maybe for four months, and they have never been round to their boyfriend or girlfriend's house. They are starting to ask questions, and want to find out about that person's background. This can happen when a single mother with children is in a relationship, and they want to check who the person is that is spending time with their children. There are cases where people think they are going out with a Special Forces commando and we find out they actually deliver pizza. Or those who say they are bachelors, who turn out to have a family or long-term girlfriend who is unaware they are on the dating scene. Some people already know that something must be very wrong.

There is a standard field kit: low-lux cameras that take pictures when there is very little light, long-range lenses, binoculars and hidden cameras. Most of our work is done with digital cameras: video film is not used at all any more. Though a client can bug their own phone, only someone very foolish would be making calls off their own landline. With the advent of mobile, it's not done as much as it used to be.

A lot of our detective work can involve following paper trails; finding out birth, death and marriage records, finding out whether people have children, and building up in-depth legal information on that person. Newspapers use PIs and always have done, but since the Data Protection Act, you have to be very careful about what you do, and more importantly, what you don't do. Fortunately, it is not illegal to know things, but you need to be able to account for how we find information out.

The Data Protection Act, which has changed our work a lot, is in some respects very fair. But in other respects it is not. For example, if a pensioner has just retired, put all their savings aside to build a conservatory, and their builder puts down their tools and abandons the job, the pensioner may just be left with a mobile phone number for the builder. We are often blocked in our abilities to find out who the person is to help these people, and it feels like we are protecting the criminal more than protecting the pensioner.

Our firm is very well-established, it has been running 30 years, and most people come to us by referral. Almost 90 per cent of our cases are referred to us by solicitors and official bodies. This can be by divorce lawyers, insurance companies or investigations into people stealing intellectual property rights (copyright theft). So an agent may disguise themselves as a courier to go into a factory or warehouse to see if fake designer goods - such as Burberry hats - are being produced.

The rest are members of the general public who come to us off their own backs. The most rewarding part of the work is tracking down missing relatives or adoptive parents, where the Salvation Army and social services have failed to make any progress. In cases like this, the last address a client will have for a person can be 40 or 50 years old.

It is a fine line between emotional detachment and empathy. We have to remain objective in what we are looking for. I have heard of cases of investigators saying to people: "We've got him, we've got him." It may be a result for the PI, but tends not to be a great result for the client. We are dealing with people's lives when they are at a real nadir, and you simply could not sensationalise that.

Charles Tomlins-Young, the director of AAPM Investigations, based in central London (020 723 3030) was talking to Genevieve Roberts.

On their cases

Ingrid Tarrant

Chris Tarrant's wife called in a private investigator (PI) when she became convinced her husband, the host of Who Wants to be a Millionaire, was having an affair. It is believed that the detective cost her £30 an hour. Tarrant finally admitted the affair, but it is not known whether Mrs Tarrant already had independent evidence. This week the couple announced that they were to separate.

Diane Thatcher

Private investigators confirmed that her husband Mark, the son of Lady Thatcher, had been unfaithful. In an interview she said: "I could no longer trust him,'' adding: "That's the most horrific thing about infidelity.''

Michael Jackson

The star called in the Hollywood investigator Anthony Pellicano when he was accused of molesting a 13-year-old boy in 1993. Pellicano found boys befriended by Jackson to testify he had never harmed them. No charges were brought in the 1993 case. The legality of Pellicano's methods has been the subject of recent speculation - he is currently in jail facing charges over alleged wiretapping and he recently completed a 30-month sentence for possessing firearms.

Eddie Murphy

Paul Barresi, a former porn star turned freelance investigator, was reportedly hired by Murphy's lawyer when the actor was arrested for picking up a transsexual prostitute. No charges were ever brought. Marty Singer, Murphy's lawyer, has refused to comment on the use of a PI.

Nicole Kidman

The actress discovered telephone conversations to her ex-husband Tom Cruise had been recorded after they announced their divorce. The conversations were found on computers seized from the PI Anthony Pellicano. There is no suggestion that Cruise knew about the recording or that the couple were ever clients of Pellicano.

Mariah Carey

The singer hired a private detective to spy on her former husband Tommy Mottola, the head of Sony. Jack Palladino, a San Francisco-based detective, said the singer was concerned that Mottola was conducting a campaign to wreck her career. Mottola said that allegations he may be trying to hinder her career were untrue.

Chris Rock

A spokesman has revealed the comedian also hired Anthony Pellicano, in this case to investigate the model Monika Zsibrita, 33, who claimed he was the father of her unborn child in 1999. An indictment now accuses Pellicano of using his connections with a police detective to illegally run a background check on Zsibrita.

Additional research by Abigail Outhwaite