A United Kingdom judge ruled Thursday that Virgin Media, BSkyB, BT, and other British telcos must block access to BitTorrent sites Fenopy, Kickass Torrents, and H33T.com.

In a written decision, Judge Richard Arnold said that these sites enable copyright infringement “on an industrial scale.” Last year, another British court ruled that The Pirate Bay must be blocked because it allows for significant copyright infringement.

However, a recent study from a UK-based music industry analysis firm confirms what we’ve long-suspected: its data shows that blocking sites that enable unauthorized downloads does little to impact actual piracy.

“Data around the blocking of Pirate Bay in the UK last April showed little negative impact on file sharing, which would have been due to the slew of copycat sites set up on proxy servers,” Gregory Mead, chief executive of Musicmetric's parent company Semetric, said in a statement on Thursday.

“Blocking websites isn’t as simple as shutting down a market stall selling copied videos or CDs, and web pirates can be very slippery.”

The study also showed that legal alternatives, such as Spotify, iTunes, and other similar services actually did more to curb piracy than outright blocking—which, as Ars users likely know, can easily be spoofed through the use of VPNs, Tor, and other circumventing technologies.

The Musicmetric report, which was released in September 2012, notes that: