As the summer music season kicks off, a new YouGov poll has found that more than one in five British festival goers - and one in three women - have experienced sexual assault or harassment while attending a festival.
In women under 40, and in all people under 25, the figure was almost half, and 70% of victims said the perpetrator was a stranger.
What's known as "bystander apathy" is seen by charities as compounding the problem, so what should you do if you witness it? Is it OK to step in?
"We know statistically that people who have been harassed or assaulted, the majority have wanted people to step in to the situation," said Jen Calleja, co-director of the Good Night Out Campaign. "If people see something happening and don't step in, it gives the person being harassed the message that the harassment isn't important, and that they're not important. It makes them feel like it's their problem, rather than everyone's problem."
1. Be aware of what to look out for
Rape Crisis defines sexual harassment as "unwanted behaviour of a sexual nature that you find offensive or which makes you feel distressed, intimidated or humiliated." This includes your body being stared or leered at, and unwelcome sexual advances and touching. Sexual violence is "any unwanted sexual act or activity", including sexual assault.
"Be alert if a person appears really uncomfortable with the way someone is talking to them, or invading their personal space or touching them," Katie Russell, a spokesperson for Rape Crisis, said. "It's often about non-verbal clues; if someone looks very tense or is frozen still."
2. Have a zero tolerance policy towards friends' inappropriate behaviour
"Often there's a culture to stay silent when people feel uncomfortable about something a friend has said or done - particularly sexual harassment," Russell said.
"Tell them that you don't think it's OK. People who routinely harass and demean women in particular are encouraged to keep doing it if their behaviour isn't challenged, because they assume other people find it funny or agree with it."
The Good Night Out Campaign say that confronting someone you know in a one-on-one conversation is more effective in the first instance than a public 'call out'.
3. If you witness a stranger being sexually harassed or assaulted, engage with them first
Rather than squaring up to the aggressor, both Rape Crisis and the Good Night Out Campaign advocate first checking in with the victim and ignoring the harasser or attacker.
"Address the potential victim directly," Russell said. "Get eye contact and ask them, 'Are you OK?', 'Is there anything you'd like me to do?', or 'Do you need some help?'
The Good Night Out Campaign suggests creating a distraction by starting a conversation, getting in the way by dancing between them, or pretending you know the person being harassed.
It's important not to speak on the victim's behalf. "Sexual harassment can be really intimidating, humiliating and demeaning, so coming to the rescue and speaking for someone who you don't even know, could be experienced as disempowering too," Russell said.
Calleja added: "It's about prioritising the victim. If you go directly to the harasser, the victim feels like further power is being taken away from them in a very traumatic situation."
4. Only challenge the perpetrator if it's OK with the victim
"Once you've discussed it with the victim and established what they want to happen, then it's OK to say to the aggressor, without speaking on their behalf, 'I find that kind of language offensive and I think it's inappropriate and unacceptable,'" Russell said. "Own your own opinion about it."
Good Night Out Campaign guidelines advise to use neutral body language and to keep it short and clear. Becoming aggressive isn't helpful, so stay calm.
5. Always assess whether it's safe to intervene if someone is being if someone is being sexually assaulted
Situations could escalate and become violent, so it's important not to put yourself in any danger. "If it's a more serious situation, if there's obviously a physical struggle or, for example, [the victim] seems very drunk or on drugs, and it seems like someone is trying to assault them, then there has to be an element of risk assessment," Russell said. "If it's clear someone is in immediate danger, get help from festival security."
Calleja advised to only intervene directly if you can prevent the situation escalating, without putting yourself in any danger.
6. Respect the victim's wishes
It's important to listen to the victim and not to jump to conclusions about what they should or shouldn't do after being sexually harassed or assaulted. But, with the victim's permission Russell said, it's "perfectly appropriate" to report the incident to festival staff.
"Let the targeted person take the lead on the next steps, if they want to be left alone, respect that," Calleja said.
She stresses that the Good Night Out Campaign want everyone to feel like they can do something to help. "So often people will just walk by or think that it hasn't really got anything to do with them, and that the person might not want them getting involved, but we know on the whole, this isn't the case," she said.