Police officers could find themselves on the wrong end of a citizen’s arrest if they follow advice issued by Home Secretary, Alan Johnson, after the European Court of Human Rights slapped the UK's stop and search laws.

According to government lawyers, however, so long as officials are "only obeying orders", there is little the ordinary citizen can do to resist them.

A bizarre Looking Glass scenario opened up this week as the European Court of Human Rights, sitting in Strasbourg, finally ruled on the case of two protesters stopped and searched at the Defence Systems and Equipment International Exhibition in 2003 under the notorious s44 of the Terrorism Act 2000.

This law gives police powers to stop any individual within "designated areas" and search them for material related to terrorist actions without having to show "reasonable cause" to justify their actions: it is the basis for much of the current tension between police and photographers.

Although the court ruled that the exercise of this power was unlawful under article 8 of the Human Rights Act – the Right to respect for private or family life – the Home Office responded instantly with a statement asserting "business as usual". The Home Secretary said:

"Stop and search under section 44 of the Terrorism Act 2000 is an important tool in a package of measures in the on-going fight against terrorism.

"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."

The difficulty with this response – which is already being echoed in guidance issued by ACPO and individual police forces – is that the UK Government lost its case in Strasbourg, and were ordered to pay costs to the defendants. No fine was levied in this instance – but continued government resistance to the Human Rights convention seems bound to bring on heftier penalties. Furthermore, unless the government changes the way the law is applied, then there is no reason to expect any similar cases not to go the same way.

If the police apply the law in the same way as they did before this ruling, then expect growing numbers of protesters to take the police to court and to extract serious money from them in the form of costs and damages.

However, the potential consequences could be far worse. According to Robert Brown, a partner with specialist criminal law firm Corker Binning, where an arrest is not lawful, it could well amount to "false detention" – itself both a civil matter and a serious criminal offence.

False detention is, in fact, sufficiently serious an offence that an individual arrested in this way could potentially respond by carrying out a citizen’s arrest on the arresting officer.

But be warned. Without cast-iron evidence, the chances of making such a charge stick are slight, and the would-be good citizen is just as likely to find themselves facing a charge of resisting arrest. El Reg therefore expressed its surprise at the advice given to the Home Office, and were even more surprised by the response.

The Home Office claim that they have already thought through these possibilities. In a further statement, a spokeswoman for the Home Office told us: "The Office of Security and Counter Terrorism (OSCT) has sought Counsel advice as to the status of existing Authorisations and over what message those forces affected should issue to their staff. Counsel’s preliminary view is that, "in terms of domestic law, the police should for the time being be protected by Section 6(2)b Human Rights Act in acting under Section 44".

"This section provides that a public authority which is acting so as to give effect to primary legislation which cannot be read in a way which is compatible with the Convention, does not act unlawfully."

In plain English: even if a particular law is "unlawful" an official acting in compliance with that law would not themselves be acting unlawfully. Or, to put it another way, some 60 years after the Nuremberg Trials, the UK government appears to have enshrined in UK law – in the Human Rights Act, no less – the principle that no matter how illegal a law, so long as officials are merely obeying orders, they cannot be held responsible for their actions. ®