A 39-year-old man has been arrested for using someone else's broadband connection without permission.

The man was sitting using his notebook computer outside a house in Chiswick, west London, when two police officers spotted him. After admitting that he was using an unsecured Wi-Fi connection without permission, he was arrested, The Guardian says.

Using an unsecured wireless connection is a criminal offence, said Detective Constable Mark Roberts of the Metropolitan police computer crime unit.

"This arrest should act as a warning to anyone who thinks it is acceptable to illegally use other people's broadband connections," he told The Guardian.

"To do so potentially breaches the Computer Misuse Act and the Communications Act. Computer users need to be aware that this is unlawful and police will investigate any violation we become aware of."

Only a handful of people have been prosecuted under the Communications Act since it was introduced. The 39-year-old Wi-Fi snatcher was released on bail until October while the investigation carries on.