April 2018. Crowds swarm the streets of Madrid. "It's not abuse, it's rape!" voices rage. "If you touch one of us, you touch all of us!"

A Spanish court had just acquitted five men of raping an 18-year-old girl at a Pamplona festival. Footage of the assault, filmed on an attacker's phone, showed the victim immobileDoctors say that during sexual assault a victim's body will often freeze or go limp as a natural response to being under threat. with her eyes closed.

Judges interpreted this as consent because Spanish law stated that rape must involve violence and intimidation. The men were convicted on a lesser charge of sexual abuse.

Anger continued to grow, and in July the government announced reform. From now on "yes means yes" and everything else, including silence, means rape. Supporters say the policy will remove the onus on the victim to prove they fought back.

More than 10 countries in Europe have made similar changes, including Sweden just weeks previously, but the model of affirmative consent first emerged in the US.

In 1993, Antioch College in Ohio was widely mocked for introducing an "ask first" policy in response to escalating assaults on campuses. Student activists spread the movement for an "explicit, informed and voluntary agreement" to sex across the country, and several states have since introduced affirmative consent laws.

There is disagreement among activists over whether consent must always be a verbalised "yes". Some worry that applying the "ask first and ask often" rule to real-life situations could get ridiculous. "Do I have to ask to move an inch closer?" one student wondered.

Spanish lawyers say non-verbal signals count as consent if someone is "actively taking part and enjoying" themselves.

But the difficulties of relying on body language were highlighted by the case of comedian Aziz AnsariA woman who went on a date with Ansari told her story to Babe.net. She says he pressured her to take part in sexual activity despite her repeatedly telling him that she would like to slow down.. The woman who accused him of unwanted advances said he "ignored clear non-verbal cues" that she was uncomfortable. He responded that he was "surprised" as their encounter seemed "completely consensual".

Absolutely, say some. The absence of a clear "no" doesn't mean a person is enjoying themselves. A victim may be scared of angering their attacker by resisting, and it is common to freeze when your body feels threatened. Sex is about having fun with a partner who has chosen to share the experience, and putting this into law is a big step forward.

It's impractical, argue others. Realistically, couples aren't going to stop to ask before every sexual act. It would be awkward and unnatural to insist on it. Everyone should be able to express what they want in sex, but this is going a step too far. Besides, it's hard to see how it could lead to more convictions because it's still one person's word against another's.