UK internet service providers have begun blocking access to websites that provide a list of Pirate Bay alternatives, as part of the battle against online piracy.
Under a court order, ISPs already block access to many of the biggest sharing sites that carry illegal content, including Pirate Bay.
But users can visit so-called proxy sites that bypass the restrictions.
One of the newly blocked sites said the ban was "totally unreasonable".
Growing list
Under a High Court ruling in a case brought by rights holders, it was agreed that ISPs would ban sites on a list that could be regularly updated.
Rights holders include music industry body BPI and the Premier League.
"Under existing BPI blocking orders relating to 63 illegal websites, ISPs are required to block the illegal sites themselves, and proxies and proxy aggregators whose sole or predominant purpose is to give access to the illegal sites," according to the BPI.
Virgin confirmed that it, along with the other major ISPs, was now blocking proxy sites in line with the original ruling.
"Virgin Media is required to block certain sites by the UK High Court. As a responsible ISP, we comply with court orders addressed to us."
'Censorship'
Among the blocked sites are piratebayproxy.co.uk, piratebayproxylist.com and ukbay.org.
The operator of UKBay.org, identified just as Dan, told piracy news website TorrentFreak that the new bans were "totally unreasonable".
"To block a site that simply links to another site just shows the level of censorship we are allowing ISPs to get away with," he said.
"UKBay is not even a PirateBay proxy. It simply provides links to proxies. If they continue blocking sites that link to sites that link to sites, there'll be nothing left."
Code:http://www.bbc.co.uk/news/technology-31832137