While I'm grateful for the editors' help in clarifying my tangled prose, my point has been lost in the rephrasing: "Of course, they'll have an actual cause, such as being uncooperative with officials or some such pretext."

The issue is precisely that the motive of police action and its pretext may differ. Given the absence of a requirement for what Americans call "probable cause" in terrorism legislation, it has the capacity to become the pretext for oppressive state activity, including fishing expeditions. The worrying thing about the news item is that re-arrests amount to a hint that this may be happening.

As far as I'm aware, all the charges so far made according to the report are non-Terrorism Act offences, which could have been prosecuted without it. Thus the Terrorism Act has been used, in effect, to avoid the reasonableness criteria and other restrictions on police powers. It is very tempting for any police force to escape potential criticism of its actions. What needs very close watching is to what extent effective avoidance of the controls of reasonableness becomes intentional evasion.

There's a further issue to consider, too. The question of prejudice.

When the charged offences come to trial, the fact that the initial arrests and searches were made under terrorism powers will be presented to the court. The reason for such investigation is not subject to testing. It will doubtless be put down to "intelligence received". (It is presumably precisely because of the requirement to protect intelligence methods and assets that the reasonableness of suspicion need not be questioned in terrorism offences.)

A court will then consider the case against the accused on another charge while subject to the presumption that Special Branch or the Security Service have (implicitly, good) reason to be interested in them. Intelligence is often speculative, and frequently defective, but it will be very hard for the defence to get this pseudo-context set aside in the mind of the court.