Phone directories business Yell is suing tycoon John Caudwell's Phones4U group for allegedly ripping off huge chunks of its internet database.
The Yellow Pages business is seeking damages of more than £100,000 from Phones 4U and sister company 4UBusiness and is seeking injunctions preventing Caudwell's firms from using the data again.
Legal documents seen by Financial Mail claim Yell caught out Phones4U by placing phoney data - or 'seeds' - on its website designed to trap anyone copying information for commercial gain.
Yell claims that Phones4U illegally copied its database so it could then sell its products, such as airtime packages, to the companies on it. But anyone calling the fake companies to sell them goods and services was directed to Yell, which logged the caller's details, according to the legal documents.
Yell claims that Phones4U and 4UBusiness contacted seeds, including 'The Bubbins Group (Builders)' and 'Pidlsey and Sons (Landscapers)' between March and December last year and lists 22 contacts allegedly made by Caudwell's companies.
Yell claims breaches of its website's conditions of use and is seeking additional damages under copyright laws. Yell complained to Phones4U in December 2003 but soon afterwards says it detected further illegal activity and another letter was sent. Phones 4U wrote back requesting clarification and sent a further letter in April last year, saying it had taken steps to prevent unauthorised use. But Yell claims Phones 4U has failed to guarantee that it will stop using information wrongfully obtained from the database.
The writ will be embarrassing for billionaire Caudwell, famous for his company-promoting charity bike rides. A Phones4U spokesman refused to comment.
Yell said: "We take safeguarding our intellectual property extremely seriously and will take strong action to protect it."