Home Office advice to Police Forces in the UK is wrong in law and likely to leave cash-strapped police authorities incurring some very large legal bills over the coming months.

That was the view given to El Reg today by Matthew Ryder, a barrister specialising in police powers and human rights.

Following the recent ruling by the Strasbourg Court of Human Rights that s44 of the Terrorism Act 2000 constitutes a breach of article 8 of the Convention on Human Rights, and the Home Office’s claim that the powers remains lawful on the basis of s6(2)b of the Human Rights Act, he told us:

"The section 6 exemption applies only where a public authority is required by an Act of Parliament to exercise powers in a way which is not compatible with Convention rights. Hypothetically, this could occur if a statute required the police to treat suspects in a way which Strasbourg had said was unlawful. Until the statute was repealed there would be a mismatch: such action would be unlawful under Convention law, but not under domestic law.

"However, section 6 of the Human Rights Act does not arise in this case. There is no compulsion on the police to continue using section 44 in the manner that was criticised by the European Court of Human Rights as "insufficiently circumscribed" and without "sufficient safeguards". The police always have a discretion as to how to use the powers granted to them by section 44 of the Terrorism Act 2000. They must now change their practices to bring them into line with the ruling.

"Any force and/or officer continuing to use s44 in the way it was used in the past, will be acting unlawfully. They will certainly be opening themselves up to a claim for damages at the Strasbourg Court. Furthermore, claims could be brought domestically as well. The fact that the House of Lords previously sanctioned the broad use of section 44 does not prevent the Supreme Court reconsidering the issue and finding the conduct unlawful under domestic law, in light of the Strasbourg ruling."

For those feeling bogged down in the legal technicalities here, the underlying issue is pretty simple. Last week, the Court of Human Rights ruled the use of s44 of the Terrorism Act unlawful.

The Home Office responded by announcing business as usual, with the Home Secretary stating: "I am disappointed with the ECHR ruling in this case as we won on these challenges in the UK courts, including in the House of Lords. We are considering the judgment and will seek to appeal. Pending the outcome of this appeal, the police will continue to have these powers available to them."

This left us puzzled: if an action is declared unlawful, it is unlawful no matter how useful the power may be to government. We asked the Home Office to explain this riddle to us, and they responded by claiming that their own legal experts (Counsel) had advised them that even where a law was itself unlawful, a public official would not be acting unlawfully if they made use of it.

Matthew Ryder’s opinion puts this into context. The exemption referred to in the Human Rights Act only covers instances where a public official has no alternative but to enforce a particular law – over mandatory sentencing, for instance, or levying of a particular tax – and this is absolutely not the case in respect of s44.

When we returned to the Home Office to ask if their Counsel had any further reaction to Mr Ryder’s opinion, they declined to comment, reverting to the statement issued in the first place by the Home Secretary. This official position – essentially placing fingers firmly in ears and going "la la la" – could cost Police Forces dear.

The Home Office statement has been adopted by ACPO and individual police forces as an accurate statement of the law. Whilst resisting arrest is ill-advised, several lawyers have pointed out that where a police officer is relying on what is essentially an unlawful law to govern their relations with the public, they are no longer protected should an individual decide to resist the application of that law.

If a member of the public chooses to sue a police force – for instance, for wrongful arrest - that force may argue that "they were only following Home Office guidelines". A court may agree with this position or – since the actions of individual police forces are the responsibility of their respective chief constables – a court could decide that the force had acted negligently in not taking advice for itself.

The one possible ground that police could yet rely on – and possibly the ground that the Home Secretary is also hoping will be of some assistance – is that courts will go easy on police officers acting unlawfully pending an appeal. If they do not, this latest advice from the Home Office could count as some of the worst it has ever given. ®