Thousands of proxies for torrent websites, which allowed users to circumvent court-ordered blocks on sites that share pirated media, have mysteriously disappeared.

As TorrentFreak reports, many popular proxies to torrent websites like The Pirate Bay, KickAssTorrents and ExtraTorrent have vanished, leaving users unable to access the websites.

Proxies work by duplicating or 'mirroring' torrent websites that have been blocked by court orders due to copyright infringement.

By reproducing these websites under another domain name, they allow users to get around the block and access them.

However, these mirrors are in breach of the law too, resulting in a constant cat-and-mouse game between torrent site owners, proxies, users and the authorities.

Now, it appears that thousands of these proxy sites have disappeared, with some offering the domain names for sale on generic landing pages.

Research by TorrentFreak found that many of the sites were connected to ProxyHouse, a large operation that runs proxy sites for other torrent websites. Even the ProxyHouse domain is now defunct and up for sale.

Why the sites were shut down is a mystery, but it could be due to legal action by the film and music industries, whose content is illegally downloaded through these sites.