BT is offering PC customers free Internet telephone calls to anywhere in the UK if they sign up to broadband in December.

To take advantage of the offer it is necessary to sign up to broadband online, and be a BT Together fixed-line customer. The offer is limited to the first 50,000 people who sign up.

The offer is only open to PC customers – it is necessary to use BT Communicator Internet telephony software – which is not available for Mac use. A microphone and speakers or headset are also necessary. The free calls do not include calls to mobiles, premium numbers or international numbers.

Jupiter Research Ian Fogg told BBC: "Broadband and telephony are attractive to customers and BT wants to make sure it is in the first wave of services."