Although the High Court ruled the banning of Palestine Action is unlawful, the Metropolitan Police has decided not to wait on the outcome of an appeal and to pretend the government has already won it. Officers will restart arresting people under the Terrorism Act https://news.met.police.uk/news/met-issues-revised-position-on-palestine-action-support-507641
The appeal ruling is not that far away: as Palestine Action co-founder Huda Ammori said at Netpol's "State of Protest" report launch last night, it's only a month away, at the end of April.
It is apparent the Met is nervous about a backlash from the media over a planned mass action on Sat 11 April

