Tim Bray, XML collaborators and Google Android Development Ambassador, submitted a new draft HTTP status code for webpages that cannot be displayed due to legal restrictions. The new status code is "451 Unavailable for Legal Reasons", visitors will know that the requested webpage or resources are inaccessible for national review Reasons.
According to draft 451, the use of code 451 should specify the detailed legal restrictions and the types of resources behind the law enforcement agencies and restrictions. Previously, the British ISP used "403 Forbidden" when following court orders to block the Pirate Bay. Some blogs pointed out that the 403 status code represents "the server refused to fulfill the request ", but in fact, the Pirate Bay server did not receive a request, so the 403 status code is not suitable. According to Bray's proposal, the 451 status code is optional.