Emperors Club VIP has many clients around the world but one British-based customer is attracting more attention than most.

Named in documents filed with a US court as “Client 6”, he paid £500 to a prostitute known as Astrid in London on January 12.

The pair met at about 9am at an undisclosed location for about an hour. After the appointment Astrid said that “everything was fine” but Client 6 called the company to say that, while she “was very nice”, “next time he wanted to see someone else”, the documents show.

It is not known if he was just visiting London on business or lives in the capital. Either way, he joins a list of other clients around Europe who are worried that they, too, will be caught up in the FBI investigation.

While existing customers may be worried, any international playboys wishing to use the services of the escort agency while in Europe may be disappointed. Calls to its offices in London, Paris and Zurich are met with a recording from the same sweet-voiced woman: “Please leave your name and number and we will contact you shortly.”

Unfortunately for potential clients, the message goes on to inform them that the tape is full and that no more messages can be taken.

The American offices are also unable to take messages. Either they are extremely busy or a lot of journalists have been ringing since Eliot Spitzer was implicated in a prostitution ring.

The Emperors Club website, now taken down, is said to have boasted that “introducing the most impressive models to leading gentlemen of the world is our expertise ... We act for a select group of educated, refined and successful international clients who give their best in all they do and who, in return, only wish to receive the best. Catering to clients who will not compromise in any area of their life ...”

The high-class escort agency is run with almost military precision and secrecy, something that may have appealed to the Duke of Westminster, who was exposed as an alleged client in the News of the World last year.

A Scotland Yard spokeswoman said that there was no investigation into Emperors Club, despite its notoriety. It is not illegal to run an escort agency supplying women as companions.

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