However, the requirement that a UK government adheres to EU rules on net neutrality may disappear at some point in future when the United Kingdom leaves the European Union.
Wide-scale inadvertent 'overblocking' has been observed since ISP default filtering was introduced at the end of 2013.
It required BT to use Cleanfeed to block its customers' access to the site.
BT did not appeal against the ruling and put the required block in place on 2 November 2011.
The range of content blocked by ISPs can be varied over time.