More than 50 British protest groups are claiming that Facebook has taken down their pages over the weekend.
On Friday, UCL Occupation, which campaigns against university fee increases, reported that Facebook had taken down pages ranging from Save NHS to York Anarchists.
Facebook has told some of the groups that their pages were moved because they were technically in violation of the site's terms and conditions. They were using a personal profile to represent a group, rather than a Group or Page.
But UCL occupation suggests that the timing of Facebook's decision shows other motives at work.
"It may well be that these groups are technically in violation of Facebook’s terms of agreement, but the timing – on the royal wedding and May day weekend – is deeply suspicious," says the group.
"We don’t know for certain, but this purge of online organising groups could be linked to the wider crackdown on protest by authorities in Britain. Either way, it is a scandalous abuse of power by Facebook to arbitrarily destroy online communities built up over many months and years."
The Open Rights Group points out that while the deleted groups were technically in breach of Facebook's terms and conditions, it was only British pages that were pulled - and only left-wing political pages, at that.
"While these groups may have technically breached their terms and conditions by using a 'profile' rather than a 'page', these deletions do not appear to have happened elsewhere in Europe or the USA, which has led to suspicions that Facebook may have been acting after a law enforcement complaint," says the ORG's Jim Killock.
"As the deletions took place on a news day dominated by the Royal Wedding, this has further fuelled suspicions. Whatever the reason, Facebook are exercising very significant power over political activity and speech as a result of their huge user base."