Known for attempting to censor a variety of Internet sites and even SMS messages, the authorities in Pakistan have today flicked the switch on some of the world's largest torrent sites. The Pirate Bay, KickassTorrents, Torrentz and ExtraTorrent are now censored for unknown reasons but the blockade doesn't stop there. In addition to silencing the torrent giants, Tumblr and world famous atheist Richard Dawkins are also facing a blackout.

All around the world governments are ordering Internet service providers to hide away content they feel is unsuitable for their citizens’ consumption.

China blocks thousands of websites on political and social grounds and web blocking of torrent and other file-sharing sites is becoming a regular occurrence around Europe.

While much of this censorship is carried out locally, countries sometimes look beyond their borders for the technological know-how to black out parts of the web.

A report published last month by Citizen Lab revealed that a Canadian filtering company called Netsweeper had been helping the Pakistan Telecommunications Company Ltd to achieve just that. PTCL is a dominant ISP owned by the Pakistani government so censorship tends to follow their ideals.

The report, titled ‘O Pakistan, We Stand on Guard for Thee’, found that in addition to employing Netsweeper’s technology, Pakistan had also been using DNS tampering techniques to render sites inaccessible.

“Netsweeper technology is being implemented in Pakistan on PTCL for the purposes of political and social filtering, including websites relating to human rights, sensitive religious topics, and independent media,” the report explained.

Thousands of sites are blocked in the country, many on pornographic, religious or moral grounds. In the past Twitter and Facebook have been banned, and YouTube was blocked following the “Innocence of Muslims” controversy.

Some of this censorship is actually welcomed by Pakistani citizens, as can seen by comments on Twitter yesterday which expressed jealousy over the UK’s proposal to wipe out all porn online.

Today, however, a new wave of bannings has citizens outraged. They might put up with porn being taken underground, but wiping out the world’s leading torrent sites is another matter.

Earlier today subscribers of PTCL began reporting that sites including The Pirate Bay, KickassTorrents, Torrentz, ExtraTorrent and even Mininova are now being blocked by their Internet service provider.

While some users reported that their private torrent sites are still accessible, there are reports that private tracker TorrentLeech has also been banned. Isohunt apparently remains accessible along with many Pirate Bay and Kickass proxy sites.

A subject of a previous banning due to Netsweeper classifying it as porn, Tumblr is now being blocked again.

In a move that’s extremely likely to wind up the Anons, there are reports that 4Chan.org has also been blocked. Why that site fell victim to the censors is unclear, but it could be any one of at least a dozen reasons.

Finally, another casualty of the crackdown is the website of Richard Dawkins, who was informed of the block earlier today on Twitter and responded with a retweet.

Again, there’s been no confirmation as to why Dawkins has been targeted, but his stance towards to religion is likely to have played its part. The world-famous atheist has had a couple of disputes with religious groups in Pakistan in the past, most recently when his Foundation for Reason & Science petitioned Facebook to restore a Pakistani Atheist page after religious groups complained about its content.

Update: 24 hours later and the torrent sites have been unblocked but the bans on 4Chan and Richard Dawkins remain.