The Metropolitan Police’s written grounds of defence in the Miranda judicial review case, published on this blog today, contain a number of significant claims about how they, in liaison with the Security Service, came to stop and question David Miranda at Heathrow airport in August this year.

Lawyers for the police say (para. 28 of the grounds) that the Security Service told the police Miranda was

likely to be involved in espionage activity

which may be a reference to the offence of spying, under section 1 of the Official Secrets Act 1911; and that in the Security Service’s assessment Miranda’s carrying of leaked material fell within the legal definition of terrorism.

According to the police (para. 28) they initially felt there was not enough information to authorise stopping David Miranda but finally

the justification advanced by the Security Service was accepted.

The police also say (para. 31)

it is true that the Security Service wanted to retrieve the material which it was thought that Mr Miranda might be carrying

but that they, the police,

did not unthinkingly execute a Security Service plan.

The Security Service assessment was contained in the final draft of a document called the “Ports Circulation Sheet”, a key passage from which was published in The Observer this weekend and which reads (para. 28 of the police defence):

Intelligence indicates that MIRANDA is likely to be involved in espionage activity which has the potential to act against the interests of UK national security. We therefore wish to establish the nature of MIRANDA’s activity, assess the risk that poses to UK national security and mitigate as appropriate. We are requesting that you exercise your powers to carry out a ports stop against MIRANDA.

We assess that MIRANDA is knowingly carrying material, the release of which would endanger people’s lives. Additionally the disclosure, or threat of disclosure, is designed to influence a government, and is made for the purpose of promoting a political or ideological cause. This therefore falls within the definition of terrorism and as such we request that the subject is examined under Schedule 7.

The police case raises important questions about the extent to which Security Service thinking – specifically the Security Service’s wish to retrieve data from David Miranda – influenced the police’s decision to stop and question him. Miranda may succeed in his judicial review claim if the judges in the Administrative Court believe Schedule 7 of the Terrorism Act 2000 was used for a purpose other than that of determining whether David Miranda was involved in terrorism.

Read the whole police document and my comments on it.