An online petition set up to try and persuade the government to halt the controversial Phorm online advertising programme has attracted more than 18,000 signatures since its introduction in March.

The anti-Phorm petition is currently the fourth most popular entry on the UK government's e-petitions web site. It advises that a number of ISPs are said to be considering using the tool, or are already testing it, and asks the government to strongly consider regulating its use. BT recently began a third trial of the technology.

"We petition the Prime Minister to investigate the Phorm technology and if found to breach UK or European privacy laws then ban all ISPs from adopting its use," the petition reads. "Additionally the privacy laws should be reviewed to cover any future technologies such as Phorm."

Phorm has been heavily scrutinised by the government already and widely criticised on the web because of the way it uses browsing information to serve accurately targeted advertisements.

Although its creators claim that any data collected would be anonymous, critics suggest that it might be intrusive and could violate personal privacy, sentiments supported by the poll which currently has almost 18,400 signatures.

"The UK's three largest ISPs - Virgin Media, BT and TalkTalk - are all in talks with a view to introducing the Phorm technology," the petition reads.

"This would result in the browsing habits of the majority of the UK population being sold to a third party for advertising purposes.

"The opt out system for this technology is vague and unproven [and] even when opting out your every move on the internet might be recorded.

"Surely this must be a breach of privacy laws, if not then the privacy laws need to be changed to cover such invasive technology."

However, BT said the petition was “misleading” and “flawed”.

“The system doesn't breach privacy - it's an improvement for online privacy over what is offered today,” said Jonathan Carter, senior media manager at BT. “It's flawed as Kent Ertugrul has apparently signed up to the petition - twice!”

The deadline to sign up is 4 March 2009.