Last Tuesday's verdict against 26-year-old law student Erol Incedal was made public today after a U.K. judge lifted an order that forbade the media from reporting it.
Anjem Choudary, the former head of al-Muhajiroun, is said to be among those arrested on suspicion of encouraging terrorism or supporting a banned organization.
In combating militants, one weapon is cutting off the groups' funding from charities or outside donors. But the "Islamic State" gets its money from other means and may be immune to U.S. techniques.