A court in Rome has blocked a Vodafone promotion in Italy which suggests clients transfer their landline telephone number to their mobile phones.

Italy’s dominant telecoms firm, Telecom Italia, had appealed against the launch of the service by its rival, arguing it broke competition rules.

Vodafone have been heavily promoting their "Vodafone Home Fixed Number" product in the run up to Christmas with adverts featuring Italian football hero Franceso Totti, which allows customers to use their land line number on their mobile phones.

A court order dated last Monday bans Vodafone from selling the part of the fixed-line package that allows users to transfer their Telecom Italia telephone number to their mobile contract, effectively blocking advertising and sale of the entire package.

But Vodafone can still offer other aspects of the service, such as using a mobile phone on fixed-line terms.

Vodafone said in a statement the judge’s decision confirmed the legitimacy of its service, while the issue of the number transfer remained open.

The UK-based company in turn sued Telecom Italia in July for allegedly passing on its database of fixed-line customers to its mobile arm. Vodafone said Telecom, which controls 80 per cent of the fixed line market, monitors its own customers so it can tell which ones are using rival firms for mobile services.