The Digital Economy Act anti file-sharing legislation received a boost as the Court of Appeal upheld an earlier High Court ruling that backed the DEA.
British ISPs BT and TalkTalk had brought the appeal as the firm's argued against controversial measures in the act that would force ISPs to send warning letters to alleged illegal downloaders and to cut-off persistent offenders.
TalkTalk said that the firm would continue to find the "ill-judged legislation" while a BT spokesman said that the firm was considering next steps but welcomed the clarification that the DEA is "legally robust in the UK".
The legislation introduces the so-called "three strikes" policy which will compel ISPs to throttle internet connections or cut users off. BT and TalkTalk argued that the measures would be costly and complex to implement and that they faced a consumer backlash.
Exactly how the "three strikes" policy will work has yet to be decided by the telecommunications watchdog Ofcom.