Tiscali and Cable & Wireless told vnunet.com today that they are investigating cases of illegal file sharing after the British Phonographic Industry (BPI) asked the ISPs to pull the plug on a list of customers branded as "music cheats".
The BPI supplied details of 59 internet accounts which it claimed were being used for illegal file sharing.
"We have said for months that it is unacceptable for ISPs to turn a blind eye to industrial-scale copyright infringement," said BPI chairman Peter Jamieson.
"We are providing Tiscali and Cable & Wireless with unequivocal evidence of copyright infringement via their services. It is now up to them to put their house in order and pull the plug on these people."
Tiscali maintained that it is reviewing the information provided and will respond appropriately.
"We do not automatically suspend customer accounts on request, but on occasion do so pending investigation," said the ISP in an initial statement.
However, Tiscali admitted that it has launched an investigation and will publish a fuller response later today.
"We have looked at the information that the BPI has sent to us and we do have some questions," said a spokeswoman.
Cable & Wireless said in a statement: "Cable & Wireless and its ISP, Bulldog, have an acceptable use policy that covers illegal file sharing.
"This would normally mean that any accounts used for illegal file sharing are closed. We will take whatever steps are necessary to put the matter right."
The BPI's evidence was gathered by tracking the IP addresses of individual file sharers and matching them to the ISPs' services.
The investigation identified 17 Tiscali and 42 Cable & Wireless IP addresses which the BPI said had been used to upload significant quantities of music owned by BPI members.
Acton's warnings come as Facebook is embroiled in one of the biggest data scandals in history
The unmanned tanks could eventually be kitted with AI systems
Dubbed I-MacEtch, it will help meet demand for more powerful nano-tech
GPU firm's research unit for self-driving cars is growing