The neighbours heard Lena* scream.

It was outside an apartment block after a Christmas party in Melbourne, where she was allegedly raped.

She had scratches on her face and knee, twigs in her hair. She acted swiftly: she contacted police, went to hospital for a sexual assault kit to collect evidence.

"I was in pain and crying and begging him to stop, saying no," she says. "I managed to wriggle myself out of his grip. He threw me onto the ground … I'm screaming, 'No, no, no!"

Even so, the jury could not agree, beyond reasonable doubt, that there was not consent. The defendant, who claimed she had consented, walked free.

Lena, whose case was heard in Victoria, wonders what the reasons were.

"Do they not believe me? What did I say wrong? What did I say right? Should I have tied my hair differently? Should I have worn something different? It's like … every little thing."

The laws of consent can be bewildering and confusing – and can lead to some surprising outcomes for victims.

So how come in Australia "no" is sometimes not enough?

What is rape?

The definition of rape is sexual penetration – either vaginal, anal or oral – with another person without them agreeing to it.

The penetration could also occur with an object or another part of the body, for example, finger or tongue, into the vagina or anus of another person. It can happen for a very short time, and be just the tip of the finger or penis.

In general, there are three main elements in establishing a rape:

1. whether there was sexual penetration
2. whether the complainant consented
3. and whether the accused knew the complainant did not consent.

What is consent?

Broadly speaking, if you can prove someone had sex with someone else without that person's consent and the person knew there was no consent, they could be guilty of rape.

But what counts as consent? There are different definitions and ages of consent across all states and territories.

The Australian Law Reform Commission has encouraged a nationwide definition of consent as a "free and voluntary agreement". But, as things stand, there is no nationwide definition and consent remains a complex issue before the law.

It remains confusing in the community as well, according to the National Community Attitudes Survey 2017, which found that 15 per cent of people believed rape within marriage was OK if a wife first came onto her husband before pushing him away. It also found that 12 per cent of respondents believed women said "No" when they meant "Yes".

Rena Ou Yang, the co-founder of Empowered Together, a Victorian non-profit focusing on preventing sexual assault through workshops in schools and the community says some questions she is asked are baffling.

"In no sex scene in a movie, or very rarely, is there ever consent specifically asked for so students don't have that in their mind as a reality," she said.

Other students, she explained, want to get consent in writing to protect themselves and find consent laws "challenging" to understand.

"'Can I get the person I'm with to sign a contract', is something we get asked. We also get asked, 'What if people are really drunk? Is it sexual assault?'," she said.

University of Melbourne criminology lecturer Bianca Fileborn says many people hold some "pretty problematic understandings of consent and what constitutes consent".

"It's problematic if they are bringing those attitudes to a jury. It plays into your idea of what 'reasonable' is – with the potential to contribute to defendants being found not guilty," she says.

Some of these problematic understandings of consent have been tackled by New Zealand comedy duo Flight of the Conchords in their song A Kiss is Not a Contract.

Positively communicated: consent in Victoria

Victoria has some of the most rigorous laws on consent in Australia.

Consent must be freely agreed and positively communicated, either by words or by conduct or a combination of the two. If a person is asleep or intoxicated or coerced they can't give consent. If a person wants to stop having sex during the act, they can revoke consent.

If consent is the main defence in a rape case, the onus is on the complainant's legal team to prove beyond reasonable doubt that the accused person gave 'no thought' to whether the person was consenting, knew there was no consent or that it was not reasonable in the circumstances that they thought there was consent.

Juries are directed that if a person didn't do or say anything to indicate they wanted to have sex, that's enough to show that the person didn't freely agree to it. This could be through verbal cues, facial expressions or body language.

Defence barrister John Desmond says four words should be enough to express the definition of rape: "Sexual penetration without consent. Four words, that's it."

However, the difficulty, he explains, is that in 99 per cent of cases there's a question of whether the accused knew that the person wasn't consenting and went ahead with it anyway – a concept called mens rea, which is Latin for guilty mind.

Desmond says a jury member might think, "I've seen her in the witness box, she impresses me as a credible witness, I think she was telling the truth. But also I believe this bloke. I think he had an honest belief that he thought she was consenting."

And in that case, the accused is acquitted.

Affirmative and enthusiastic? The situation in NSW

Issues surrounding consent have been highlighted by a particularly controversial case in NSW. In 2015, Luke Lazarus, the son of a wealthy Sydney businessman, was convicted of sexual intercourse without consent after a jury trial in the NSW District Court. He was sentenced to a maximum five years’ imprisonment with a three-year non-parole period. In 2017, after he had served 11 months, the conviction was quashed in a judge-alone decision in the Court of Criminal Appeal.

In both the trial and the appeal, the cases turned on Lazarus's belief about consent during the events of an evening in 2013. He said he believed Saxon Mullins, then an 18-year-old virgin, consented to sex with him in an alley near a Kings Cross nightclub.

In NSW there's no requirement that consent be positively communicated (meaning a failure to say no, does not indicate agreement). The law states that the prosecution has to prove beyond reasonable doubt that the accused either knows there isn't consent, is reckless in determining if the other person consents – for example, the accused is drunk and cannot fully comprehend if there was consent – or the accused had no reasonable grounds for believing that the other person consented to sex.

Ms Mullins and rape support services have since been pushing for consent to be "affirmative and enthusiastic".

This would mean that consent has to be actively communicated, otherwise it does not exist and someone who persists with sex could be liable for rape.

"All you need to say is, 'Do you want to be here?' and, very clearly, 'Do you want to have sex with me?" Ms Mullins told the ABC.

"If it's not an enthusiastic 'Yes', then it's not enough. If it's not an enthusiastic 'Yes', it's a 'No'. That's it. And then you're committing a crime."

A NSW Law Reform Commission inquiry on sexual consent was tabled in the state Parliament in November 2020 and recommended changes include providing that lack of verbal or physical resistance should not be taken as consent. However, the law is yet to be updated.

Mistake of fact: drunkenness no longer a defence

In Queensland and Western Australia, the mistake of fact defence allows those accused of rape to say they had an honest and reasonable – but mistaken – belief there was consent.

Queensland passed new legislation in March 2021, clarifying that it is no longer a defence for those accused of rape to say they were so drunk or affected by drugs that they thought the victims were consenting.

The reforms make explicit four legal principles that can already be distilled from current case law. They include that silence alone does not amount to consent, consent initially given can be withdrawn and that being intoxicated is not relevant to the excuse of mistake of fact.

However, the Queensland Greens and anti-rape campaigners are campaigning for further changes, including moving to an affirmative consent model.

Tasmania, where consent must be ‘positively indicated’

Tasmania has similar laws to Victoria, but not everyone is happy with them either.

Australian Lawyers Alliance Criminal Justice spokesman Greg Barns calls the Tasmanian model for consent “unworkable”.

He says what counts as communicating consent could be susceptible to misinterpretation and in the context of two people in an intimate setting, it may be too clinical.

Tasmania does not set the bar as high as 'enthusiastic consent' but its laws require a positive indication of consent, meaning a failure to say "No" cannot be used as evidence of agreement.

"It's important that we be very careful in this area of law in trying to be favourable to one side or the other. The test of the criminal justice system should be fairness," he said.

Until last year survivors of sexual assault in Tasmania were not allowed to discuss their assaults under their real name to the media, even if their attacker had been found guilty.

This law was successfully challenged by 2021 Australian of the Year Grace Tame who was sexually abused by her 58-year-old teacher when she was 15. She won a court order allowing her to speak about her experience and then through the #LetHerSpeak campaign advocated for law reform.

In April 2020 the law was changed to allow Tasmanian survivors to speak out.

Northern Territory

In the Northern Territory consent is defined as free and voluntary agreement. Because of mandatory sentencing laws in the NT, an offender convicted of a sexual offence must serve prison time.

The NT had sexual-assault victim gag-laws similar to Tasmania; they were eased in July 2020 but the reforms only went halfway. Victims of sexual assault are not allowed to discuss their assaults under their real name to the media until their offender has exhausted all their appeals, which could take years.

South Australia

Similar to other states, there must be free and voluntary agreement to sex, and consent can be withdrawn during the encounter. The other person must also not be "recklessly indifferent" about gaining consent or force, threaten, humiliate, disgrace or harass another person into giving consent. Being recklessly indifferent during sexual offences means an accused has not considered the other person's wishes and has disregarded whether or not the other person has consented.

ACT

A review of consent laws is under way, after a bill was introduced to Parliament in 2018 by sexual assault survivor and Greens MP Caroline le Couteur. The ACT government is considering creating a definition of sexual consent based on a concept of free and voluntary agreement and affirmative and communicative consent, but the government is waiting on the findings from the NSW Law Reform Commission inquiry into sexual offences before it does anything.

*Names in this report have been changed.