Lord Mandelson has announced that he intends to pursue file sharers and cut off the connections of persistent offenders.

Mandelson restated his controversial plans to adopt a tougher approach to online piracy in a speech today at the Cabinet Forum.

The proposals mean that internet service providers will play a part in identifying the worst offenders, and will send warning letters before cutting them off from the internet.

Account suspension will be an option available as a last resort for the most serious infringers, according to Mandleson, who believes that a series of cajoling letters will be enough to dissuade many downloaders from reoffending.

"It is clear that, whilst unlawful file-sharing excites a strong response from all sides, it is not a victimless act. It is a genuine threat to our creative industries," said Mandelson.

"The creative sector has faced challenges to protected formats before. But the threat faced today from online infringement, particularly unlawful file-sharing, is of a different scale altogether.

"We cannot sit back and do nothing. We will put in place a fair, thorough process, involving clear warnings to people suspected of unlawful file-sharing, with technical measures such as account suspension used only as a very last resort.

"Only persistent rule breakers would be affected, and there would be an independent, clear and easy appeals process to ensure that the correct infringer is penalised."

Current offenders will not be punished until the end of 2011, according to Mandelson, who suggested that the media industry would also have to play a role. Consumers should be taught to appreciate the value of intellectual property, he said, and be able to appreciate innovative content at affordable prices.

Mandelson quoted figures suggesting that just one in every 20 music downloads is done so legally.

"A 'legislate and enforce' approach to beating piracy can only ever be part of the solution. The best long-term solution has to be a market in which those who love music and film, for example, can find a deal that makes acting unlawfully an unnecessary risk," he concluded.

Chris Watson, a partner at city law firm CMS Cameron McKenna, argued that although the news would be welcomed by rights holders and creative industries, ISPs and consumers will be less than enthused.

"The 'opportunity to appeal', as Mandelson puts it, is very different to the legal safeguards that normally apply to the determination of the infringement of intellectual property rights, and may be incompatible with the European Convention on Human Rights," he explained.

"This is especially relevant as current technology used to identify file-sharers can all too easily implicate innocent people."