The following is an excerpt from the report UK Internet Regulation Part I: Internet Censorship in the UK Today.
Read the full report here.
Copyright-blocking injunctions have one major advantage over every other system except for defamation. They require a legal process to take place before they are imposed. This affords some accountability and that necessity and proportionality are considered before restrictions are put in place.
However, as currently configured, copyright injunctions leave room for problems. We are confident that court processes will be able to resolve many of these. Further advantages of a process led by legal experts are that they are likely to want to ensure that rights of all parties are respected, and appeals processes in higher courts and the application of human rights instruments can ensure that problems are dealt with over time.
A process led by legal experts offers further advantages, including that it will be likely to ensure that rights of all parties are respected and that appeals processes in higher courts and the application of human rights instruments will ensure that problems are dealt with over time.
Copyright blocking injunctions are usually open-ended. There is not usually an end date, so they are a perpetual legal power. The injunction is against the ISPs. Rights-holders are allowed under the standard terms of the injunctions to add new domains or IP addresses that are in use by an infringing service without further legal review. ISPs and rights-holders do not disclose what exactly is blocked.
It has been reported that around 3,800 domains  are blocked by 31 injunctions, against around 179 sites or services. 
The government is preparing to consult on making copyright blocking an administrative process. We believe this would be likely to reduce accountability for website blocking, and extend it in scope. At present, website blocking takes place where it is cost effective for private actors to ask for blocks. Administrative blocking would place the cost of privately-demanded blocking onto the UK taxpayer, making it harder for economic rationality to constrain blocking. Without economic rationale,and with widening numbers of blocks, it would be harder to keep mistakes in check.
Open Rights Group has compiled public information about clone websites that might be blocked, for instance the many websites that have presented full copies of the Pirate Bay website.
We ran tests on these domains to identify which domains are blocked on UK networks. As of 25 May 2018, we found 1,073 blocked domains. Of these, we found 38% of the blocks had been done in error. 
To be clear, each block would generally have been valid when the block was initially requested and put in place by the ISP, but not many of these blocks were removed once the websites ceased to infringe copyright laws.
The largest group of errors identified concerned websites that were no longer operational. The domains were for sale or parked, that is flagged as not in use, (151), not resolving (76), broken (63), inactive (41) or used for abusive activities such as “click-fraud” (78).  At other times, we had detected three or four that had been employed in active unrelated legitimate use , and several that could be infringing did not seem to be subject to an injunction, but were blocked in any case. 
That means a total of 409 out of 1075 domains were being blocked with no current legal basis, or 38%.
These errors could occur for a number of reasons. Nearly all of the domains would have been blocked as they were in use by infringing services. However, overtime they will have fallen into disuse, and some then reused by other services. In some cases, the error lies with ISPs failing to remove sites after notification by rights-holders that they no longer need to be blocked. In other cases, the rights-holders have not been checking their block lists regularly enough. While only a handful of blocks have been particularly significant,it is wrong for parked websites and domains for sale to be blocked by injunction. It is also concerning that the administration of these blocks appears very lax. Anear 40% error rate is not acceptable.
To be clear, there is no legal basis for a block against a domain that is no longer being used for infringement.The court injunctions allow blocks to be applied when a site is in use by an infringing service, but it is accepted by all sides that blocks must be removed when infringing uses cease.
Open Rights Group is concerned about its inability to check the existing blocks. What is or is not blocked should not be a secret, even if that is convenient for rights-holders. Without the ability to check, it is unlikely that independent and thorough checking will take place. Neither the ISPs or rights-holders have particular incentive to add to their costs by making thorough checks. As of the end of July 2018, most of the mistakes had remained unresolved, after three months of notice and a series of meetings with ISPs to discuss the problem. The number by October 2018 had reduced to nearer 30%, but progress in resolving these remains very slow. 
Many blocking regimes do not offer the flexibility to add on further blocks, but require rights-holders to return to court. The block lists are entirely public in many European countries.
ISPs should at a minimum publish lists of domains that they have “unblocked”. This would allow us and others to test and ensure that blocks have been removed.
A further concern is that the explanations for website blocks and how to deal with errors is very unclear.This has no doubt contributed to the large proportion of incorrect blocks.
At present some basic information about the means to challenge the injunction at court is available.However, in most cases this is not what is really needed. Rather, a website user or owner needs information about the holder of the injunction and how to ask them to correct an error. This information is currently omitted from notification pages.
Notifications should also include links to the court judgment and any court order sent to the ISP. This would help people understand the legal basis for blocks.
Our project blocked.org.uk includes this information where available. We also generate example notification pages.
While ISPs could implement these changes without instruction from courts, they have been reluctant to improve their practice without being told. Open Rights Group’s interventions in the Cartier court cases helped persuade the courts to specify better information on notification pages, but we believe there is some way to go before they are sufficiently explanatory.
The government is considering administrative blocking of copyright-infringing domains. This poses a number of problems. The current system requires rights holders to prioritise asking for blocks where is it is cost effective to do so. This keep censorship of websites to that which is economically efficient to require, rather than allowing this task to expand beyond levels which are deemed necessary.
As we see with the current system, administering large lists of website blocks efficiently and accurately is not an easy task. Expanding this task at the expense of the taxpayer could amount to unnecessary levels of work that are not cost efficient. It will be very hard for a government body to decide “how much” blocking toask for, as its primary criteria will be ensuring material is legal. Unfortunately, there are very large numbers of infringing services and domains, with very small or negligible market penetration.
Secondly, it makes no sense for a growing system of censorship to keep what is blocked secret from the public. Administrative systems will need to be seen to be accurate, not least because sites based overseas will need to know when and why they are blocked in the UK in order to be able to appeal and remove the block. This may be resisted by rights-holder organisations, who have so far shown no willingness to make the block lists public. Administrative blocking could be highly unaccountable and much more widespread than at present, leading to hidden, persistent and unresolvable errors.
Thirdly, combining wide-scale pornography blocking with widening copyright blocking risks making the UK a world leader in Internet censorship. Once the infrastructure is further developed, it will open the door to further calls for Internet censorship and blocking through lightweight measures. This is not an attractive policy direction.
Future legislation should specify the need for time limits to injunctions and mechanisms to ensure accuracy and easy review
Open-ended, unsupervised injunction and blocking powers should not be granted
Administrative blocking should be rejected
Current injunction holders and ISPs must urgently reduce the error rates within their lists, as incorrect blocks are unlawful
Courts should reflect on the current problems of accuracy in order to ensure future compliance with injunctions
It should be mandatory for blocking notices to link to legal documents such as a judgment and court order
It should be mandatory for blocking notices to explain who holds the injunction to block the specific URL requested
Assurance should be given that there is transparency over what domains are blocked
ISPs and right-holders should be required to check block lists for errors
 https://www.blocked.org.uk/legal-blocks/errors maintains the error rates; results as of 4 June 2018 are available here: http://web.archive.org/web/20180604092443/https://www.blocked.org.uk/legal-blocks/errors.
Reports and data can be downloaded from https://www.blocked.org.uk/legal-blocks
 These categories are defined as follows: (i) Parked or for sale: the site displays a notice explaining that the domain is for sale, or has a notice saying the domain is not configured for use; (ii) not resolving means that DNS is not configured so the URL does not direct anywhere; (iii) broken means that a domain resolves but returns an error, such as a 404, database error etc; (iv) inactive means that the site resolves, does not return an error, returns a blank page or similar, but does appear to be configured for use; (v) abusive means that the domain is employed in some kind of potentially unlawful or tortious behaviour other than copyright infringement.
 A blog and website complaining about website blocking ,for instance .These were not functional as we completed the review.
 See also our press release: https//:www.openrightsgroup.org/press/releases/2018/nearly-40-of-court-order-blocks-are-in-error-org-finds
 https//:www.blocked.org.uk/legal-blocks/errors Errors on 10 October 2018 stood at 362 domains out of.1128