If you are a teacher or a health worker and you think a girl has been subjected to genital mutilation, you now must report it.
The government is going to make it a legal requirement in the coming months, although details of how the new law will be enforced still have to be worked out.
A new report estimates that about 137,000 women and girls are affected in England and Wales, with the highest number living in London.
The minister in charge of tackling female genital mutilation (FGM) admits it's "a very difficult thing".
Karen Bradley, minister for preventing abuse and exploitation, told Newsbeat: "It is the case where there is sometimes nobody in the family who thinks this is unacceptable.
"But we need to reach out to isolated communities, and say this isn't part of the shared values here in Britain. This is not the way to behave. There is no cultural, religious, or political excuse. This is child abuse."
Part of the plan to tackle it is to get more border staff at airports trained up on how to spot the signs of FGM, but also forced marriage and trafficking.
This already happens at Manchester and Gatwick airports.
At Heathrow Airport in London, 200,000 people leave and arrive every day.
How it works
Newsbeat has been to find out how spotting a potential victim works.
A couple are stopped at passport control - the woman is looking down, she can't speak English and her passport photo does not resemble her.
The officer calls for back up and asks the man to step aside while the woman is questioned.
She is asked where she is from, where she lives and if she's feeling well.
When she shows signs of discomfort and nerves, the staff reassure her and take her away.
They also provide her with a brochure explaining what trafficking is. These are available in different languages.
Ashley Robinson, an assistant director at Border Force at Heathrow, said: "There is no one sign that does it for us. It could be a combination of strange things.
"It could be they're not in control of documentation, no money belongings, they're dressed and treated differently.
"There's a thin line between a bored teenager and a victim of trafficking.
"We also look for any signs of depression or sadness."
The families who tend to get attention at Heathrow are ones returning from where FGM is performed, like Nigeria and Sierra Leone.
Forced marriages tend to be most common in the Middle East and South Asia - Pakistan and Bangladesh.
We ask if people have ever lashed out and accused Ashley and his staff of racism.
"It's something that may happen as part of the job. [The] important thing is we treat people fairly based on their merit and credibility on the day.
"This is a robust law enforcement agency, we are here to secure the border and to stop bad people and things from coming in."
Female genital mutilation generally involves removing part or all of a girl's clitoris and the area around her vagina.
Some girls as young as five have undergone FGM, which has been illegal in the UK since 1985.
This week a new Home Office-funded report found there are 137,000 women affected by FGM in the UK, with 21 women in every 1,000 at risk in London.
Karen Bradley said: "We do need to make sure we have more cases brought forward. But we have to be careful this is a difficult crime to find evidence for. We are looking at families giving evidence against other family members."
This all comes a year after the Girl Summit.
Prime Minister David Cameron said FGM and forced marriage was something that would be tackled through a global effort.
Last year Bangladesh was criticised by Human Rights Watch for failing to introduce a specific law banning forced marriages and drafting proposals to lower the age a girl could marry from 18 to 16.
Ms Bradley admits more needs to be done to change attitudes in other countries.
As far as FGM goes, there are protection orders in place which allow people to apply to a court to stop anyone from travelling abroad.
It was used to prevent two girls from going to Africa for the first time last week.
These new laws for mandatory reporting will be introduced later this year.