The Webwise ad monitoring system "is not acceptable" to most people, an online survey has revealed.

More than half of the people interviewed for the ISPreview survey said they would leave their current internet service provider (ISP) if it installed the advertising system developed by Phorm.

Webwise has caused a storm of controversy after it was announced that a number of UK ISPs were considering using it.

Although it is claimed the software monitors websites people visit so it can target ads more effectively, Phorm claims the process is anonymous and leaves no trail. However, the software has become synonymous with spyware. Privacy experts have also questioned its legality under the Regulation of Investigatory Powers Act (RIPA).

Mark Jackson, editor-in-chief of ISPreview.co.uk, said, "Consumers are sending a clear message to ISPs that they don’t want Phorm and are even prepared to leave if it is forced upon them, regardless of whether the provider is offering an opt-in solution or not. It looks like Phorm will never be acceptable to the majority, no matter how the PR is spun."

According to independent information and review website covering broadband ISPs, which collated findings from more than 1,090 people, the situation was not helped when it came to light that BT had run two secret trials of earlier versions of Webwise in 2006 and in 2007.

The study revealed that 57 per cent of people would leave their current ISP if it adopted the controversial system, only two per cent of those surveyed said they would not leave their ISP if it adopted Phorm, while 16 per cent said they were undecided and nearly a quarter didn’t know what it was.

Phorm is currently in discussions with BT, Talktalk (The Carphone Warehouse) and Virgin Media about using the Webwise software. BT is running another trial of around 10,000 users but it will be opt in this time,