A lipstick mark on the collar, an incriminating earring found down the side of the bed – these are the ways we expect cheating lovers to be found out. Not through hi-tech surveillance and hours of snooping by a paid professional.

But this is exactly what private detectives are employed to do.

The Recorder spoke to local snoop The Essex Investigator, whose name we can’t reveal for fear of reprisals, to learn more about his mysterious trade.

At the time, he was in the back of his shabby looking van covered in builders’ branding. The truth is though, he was in the midst of a 16-hour surveillance session and that “builder’s” van contained £70,000 of equipment, including seven CCTV cameras spying on the outside world.

“Here’s an interesting one,” he said. “This couple in Rainham, married for 30 years, relatively well-off. Well, she suspected he was up to no good.”

The investigator followed the unwitting husband across the borough, supposedly on his way to work. He quickly discovered that he was a dishonest man and the extent of his lies were immense.

He explained: “He had a complete other family, with two teenagers and another wife. He’d go and stay with her Wednesdays and Sundays and claim to work away the rest of the time. One was in Rainham, the other in Romford. They had no idea about each other. As far as they were concerned he went off to work in London. He didn’t even work there though.He got away with it for 15 years.”

He tells a tale of another Havering couple, one half of whom had a well-kept secret.

“A couple in their 60s, straight-laced church-going types. She had suspicions, you’d have no idea,” he said. The investigator bugged the husband’s laptop.“We found he was using gay websites. I did some surveillance and found out he was going cottaging where they meet up with blokes in fields for sex. She thought he had badminton on a Tuesday night.”

This kind of work is not uncommon, however.

He added: “Ninety per cent of the matrimonial cases where the client believes their partner is cheating, they are right. Normally I prove it in less than 48 hours. It’s sad but it’s the reality. I do it most weekends now.”

There is, of course, the other 10 per cent who are wrong.

One woman sent him off to Marbella to find out what her husband gets up to when he’s away. “He was playing golf every day with his mates,” the investigator said. “She’s talking about doing Marbella again this year. I’ve done quite a few for her when he goes away on business and he’s never done anything wrong. I’ve seen so much of the guy I feel like I know him.”

He, a man in his 30s often dressed as a builder, and a team of ex-special forces and ex-police officers work across the region, often on matrimonial cases, but also uncover benefits scammers. They search City boardrooms for hidden microphones used by rival companies to steal ideas and get ahead in the game. But how did he get into the job?

He said: “I started off when I left school. The only thing I knew how to do was steal cars so I started up a business repossessing cars.

“Part of repossessing vehicles is having to find them so I got good at finding people and following them back to their cars so I could repossess them. But after that I was being asked can you find this person or that person. Soon it evolved to what I do now.”

Bugging people’s homes and vehicles all sounds of questionable legality, but he explains that possessions are often in both partner’s names. If the wife employs him, then he doesn’t have to seek permission from the husband.

“As far as I’m concerned, the surveillance equipment is there for security purposes. It’s completely legal,” he said.

So cheating partners, benefits fraudsters and boardroom spies, beware... The Essex Investigator may already be on your case.

For more information on The Essex Investigator go to http://www.essexinvestigator.co.uk