ISP-branded VoIP offerings have edged ahead of Skype as the most popular internet telephony services in Europe.

Research carried out by network management firm Sandvine at the end of last year reported that ISP-branded VoIP represented 51.2 per cent of all VoIP minutes in Europe.

Skype followed closely behind with 45 per cent of all VoIP minutes, and Vonage took less than one per cent. Other third-party VoIP providers represented 3.5 per cent of all VoIP minutes.

The situation in Europe almost mirrors that of North America, according to the study, where ISP-branded VoIP represents 53 per cent of all VoIP minutes on broadband networks. Vonage is a clear second with 21.7 per cent share of minutes.

Skype held a 14.4 per cent share in North America, and other third-party VoIP providers captured the remaining 10.9 per cent share of minutes.

"ISP-branded VoIP is, and will continue to be, a key factor in driving revenue growth and triple-play success for service providers," said Boyd Peterson, senior vice president of media research at analyst firm Yankee Group.

However, BT and Wanadoo suffered serious outages of their respective VoIP services in the UK this month, both of which are service provider-branded.