The Police Intellectual Property Crime Unit (PIPCU) has arrested a 20-year-old man in Nottingham on suspicion of copyright infringement for running a proxy server providing access to other sites subject to legal blocking orders.

The man was questioned by police but has been released on bail. The arrest was made after police—with the support of the Federation Against Copyright Theft (FACT)—found evidence relating to the creation of a proxy server that provided access to 36 other websites that had been blocked for hosting illegal or infringing content.

The proxy server in question is Immunicity, run by the Torrenticity Group—as first highlighted by TorrentFreak—which was designed to unblock both torrent sites and proxies. It required users to make a simple change to their browser settings—adding a Proxy Auto Configuration file (PAC)—which could then instruct your browser to send your Web traffic through different proxies depending on the URL you are looking for. This means that you could access sites that had been blocked by UK ISPs following High Court orders, such as The Pirate Bay, KickassTorrents, HEET, ExtraTorrent, YiFY, and EZTV. Immunicity and similar services therefore fall foul of anti-circumvention provisions within UK copyright law.

Now, when you visit Immunicity.org, you simply see a scary-looking takedown notice from the police, along with links to places where you can find legitimate content. This is a bit concerning, particularly as Immunicity doesn't host copyright-infringing content; it merely lets users route their traffic through the proxy network in the same way VPNs do.

The arrest is part of the police unit's clampdown on piracy websites, called Operation Creative. Wired.co.uk reported on another of the operation's measures last week, which sees the police replace advertising banners on websites that are found to be hosting copyright-infringing content.

"We will come down hard on people believed to be committing or deliberately facilitating such offences," said the head of PIPCU, Andy Fyfe.

Copyright holders have been making applications for High Court orders to force UK ISPs to block websites providing access to copyright-infringing content—mainly music and movies. Invariably, these orders have been circumvented through the use of proxy servers. But it looks as though the police has now turned its attention to those very proxy servers. Watch out.

This story originally appeared on Wired UK.