The heads of some of the biggest broadband suppliers in Britain have come together to question the government's new stance on filesharing.
Last week, business secretary Lord Mandelson issued new proposals that could result in users suspected of illegal filesharing having their accounts suspended and their broadband connections disconnected.
But in an open letter to the Times, chief executives from BT, TalkTalk-owner Carphone Warehouse and Orange warned that innocent broadband customers would be caught in the crossfire.
The internet service providers said that any such action would not only be "harsh and punitive" but would also put content companies off the idea of developing new internet-specific services.
"We must avoid an extrajudicial 'kangaroo court' process where evidence is not tested properly and accused broadband users are denied the right to defend themselves against false accusations," they said.
The letter was also signed by leading members of Which?, the Open Rights Group and Consumer Focus.
Earlier this month, EntaNet made a similar argument, claiming that innocent broadband customers could be penalised because of the lack of precision with which illegal filesharers are identified.