Campaigners in favour of hardcore pornography staged an unusual "face-sitting" protest outside the British parliament on Friday against new rules banning a series of extreme sex acts from online videos.
Around 20 fully-clothed couples simulated sex on the lawn in Parliament Square, with women in black leather boots sitting astride the men's faces.
They were protesting an amendment to the Communications Act requiring video-on-demand online pornography to follow tougher rules, already laid out by the British Board of Film Censors (BBFC) for DVDs sold in shops.
Spanking, caning, penetration by any object "associated with violence", physical or verbal abuse, physical restraint and female ejaculation were among the acts to be banned from online productions.
Strangulation, face-sitting and fisting were also banned, with the BBFC deeming them "life-endangering".
"While the measures won't stop people from watching whatever genre of porn they desire, as video shot abroad can still be viewed, they do impose severe restrictions on content created in the UK, and appear to make no distinction between consensual and non-consensual practices between adults," said the Facebook page of the protest organisers.
"Adult performers are going to be affected by this," said Charlotte Rose, a former professional dominatrix who organised the protest.
She said it would "push more people into poverty".
"What the government is doing is taking our personal liberties away without our permissions," she said.
A woman named Mistress Absolute said the law was inhibiting her "sexual freedom".
"This is a gateway to other laws being snuck in," she said.
A spokesman for the government's Department for Culture, Media and Sport said the legislation provided the same level of protection to the online world that already exists for the high street sales of DVDs.
"In a converging media world these provisions must be coherent and the BBFC classification regime is a tried and tested system of what content is regarded as harmful for minors," he said.