Here’s the Metropolitan Police’s grounds – drafted by Jason Beer QC of 5 Essex Court and Ben Brandon  and Ben Watson, both of 3 Raymond Buildings – for resisting David Miranda’s judicial review claim in the Administrative Court this week. Miranda is challenging the police’s use of powers under Schedule 7 of the Terrorism Act 2000.

My view on the police legal arguments is below, after the viewer. Click on the bottom left of the viewer to see the document in fullscreen view, with my more detailed comments highlighted in yellow.

It’s the police arguments on the “improper purpose” aspect of the case that are most interesting.

The police say (para. 28) there was not enough information to make an arrest because they did not know David Miranda’s role – but also argue that even had there been, that would not have prevented the use of Schedule 7. They say they were initially of the view there was not enough information to stop and question David Miranda, but that the Security Services ultimately persuaded them of the case for doing so, set out in the final draft of the “Port Circulation Sheet”.

They say the Security Service did want to retrieve the material they thought Miranda was carrying – a claim which necessarily casts some doubt on whether the stop was influenced by purposes other than simply determining whether Miranda was involved in terrorism. The police therefore emphasise more than once that they took an independent view, and did not “unthinkingly execute” a Security Service plan.

The police argue that the conditions for use of Schedule 7 were fulfilled, based on the Security Service’s assessment (and their own analysis) that Miranda was potentially involved in disclosures which might risk lives, and which might be intended (at least by Edward Snowden) to influence government and to advance a political cause.

The police’s argument closely reflects the Home Secretary’s that the stop did not bypass other legal regimes giving special protection to journalistic material – those regimes did not apply, and the material in question was not journalistic, they say. The police’s human rights arguments again reflects the Home Secretary’s: they say this is not a case involving the identification of sources, which attracts strong protection under human rights case law. No prior judicial scrutiny is needed before material is seized.

What’s interesting about the police’s defence is the factual detail given in support of the argument that the stop was for a proper purpose. There’s clearly enough here on which the claimants’ lawyers can mount a serious argument that the Security Service’s wish to get their hands on Miranda’s data influenced and “infected” the police’s action with the taint of an improper purpose.

While the human rights arguments may attract attention, it’s this strand of the case on which the claimants stand a chance of winning, and on which in my view the case will turn.