Fake Alibi was set up in 2005 to cater primarily for men and women who want to get away with having an affair, but also for people wanting to get out of work, wanting to have a couple of days on their own or even wanting to give others the impression they are in a relationship. Despite repeated criticism about the morality of its work, the company has flourished, and now has 7,000 customers worldwide.

"If someone wants to have a weekend away on the quiet, Fake Alibi can provide false travel documents and hotel bookings that can be posted to the house, " said Kennedy. "They can arrange to have your mobile number diverted so it doesn't have an abroad ringtone and they can even arrange for you to have a photograph of yourself and all your mates at the so-called conference, or for a training certificate to be sent to your house a few days later."

But Fake Alibi is not all about extra-marital affairs, according to Kennedy. "I have a lot of case studies on people wanting to get out of work. One of the most popular things to do is call on Monday morning pretending you were away for the weekend and are still stuck in an airport. Fake Alibi then supplies background airport noises to make it authentic."

Kennedy recalls one case in her book of a so-called 'girlfriend' who called a client's boss from the 'dentist'. "She said he was having his wisdom tooth taken out and couldn't talk and dentist drilling noises were put faintly in the background, " said Kennedy. "It's pretty funny the lengths people will go to to get out of work on a Monday."

One of the most bizarre requests Kennedy came across was from a woman in the US who had organised a cockfight in her basement. Her neighbour was threatening to sue and asked Fake Alibi to provide her with a reasonable explanation for her activities. This couldn't be done.

Another impossible request came from a businessman who was being sent to China for work and wanted to get out of it. "He asked us if Fake Alibi could get a doppelganger for him, but of course they couldn't, " said Kennedy, whose book is due out next year. "They're good but they're not miracle-workers."