Rebtel, the largest independent voice over internet phone (VOIP) provider after Skype has released its research which shows that almost 60% of the UK’s total smartphone users would switch networks if they knew that their mobile operators were blocking or slowing down Over The Top services (OTT), such as Viber and Facetime.

That would account for 18 million UK subscribers.

Mobile communcations companies such as Vodafone are seeing traditional voice call and text message volumes fall, as OTT data services such as iMessage and Skype take over, which run through users data allowances instead – often for free. This means that the cost of infrastructure is going up, while the telcos margins on services fall.

"Traffic shaping is a much debated topic within the telecommunications industry and it has been brought to the attention of Berec (Body of European Regulators for Electronic Communications) who are investigating this further to understand the extent of traffic management practices and how it affects consumers’ use of services. Meanwhile, consumers are unaware of how operators are pulling the strings and are affecting how they use Skype, Rebtel or other over the top services such as WhatsApp messaging service," said Andreas Bernstrom, CEO of Rebtel.

Rebtel’s research shows that 70% of those surveyed were not clear how or why their operators were blocking these services, and felt that their operator had not communicated this practice to them formally ‘or in a way that they understood how it related to their mobile phone tariff.’ Only 8% thought it was within the operator’s rights to do so.

"This is an on-going problem for the telecoms industry and bodies such as The Internet Telephony Services Providers’ Association, the UK trade body for the VoIP industry, recently slammed Vodafone, T-Mobile and Orange for being the worst offenders when it comes to prohibiting VoIP applications," he said.