Media playback is unsupported on your device Media caption "Sexy girl! Excuse me! Yo!"

"You better learn to answer a man when he speaks to you!"

It's a rainy afternoon in east London and two women are writing these words on a pavement in coloured chalk.

The words are a catcall - shouted by a stranger to a woman walking down a street in London.

The trend of writing out catcalls started in New York and now it's spreading to other cities around the world.

The woman who started the idea says she wants to stop "street harassment".

Warning: This article contains language shouted at women which you may find offensive.

Image caption Sophie started the Catcalls of NYC account on Instagram

Sophie Sandberg and Farah Benis met on social media after Sophie started the catcallsofnyc Instagram account.

Farah was inspired, and started a similar account based in London.

Newsbeat was there when they met in person in Victoria Park in east London.

Image caption Farah writes out catcalls in London

'It's not a compliment'

"When I first came across Sophie's account it really resonated with me." Farah told Newsbeat.

She says she wants to try to raise awareness about sexual harassment on the streets.

Image copyright Sophie Sandberg

"I saw there wasn't a London version of it, and I wanted to get involved. It's a massive issue and I thought highlighting it is one way to make it stop."

She adds: "A lot of the time when people say these things there is a sense of entitlement that you have to stop. People feel they're entitled to your time."

Image caption "Let me be your Harvey Weinstein," was another catcall said to a different woman in London

Farah says she has been shocked about how many 12 and 13-year-olds have contacted her about catcalls.

'I was forced to see myself as a sexual object'

Women like Olivia, 21, who lives in New York - have contacted Sophie to share their experiences.

She says she was 11-years-old and on her way to school when a man shouted: "Hey sexy".

"It felt really gross and even though it was in broad daylight it made me feel really unsafe.

"One second I was being a child and the next I was being forced to see myself as a sexual object."

Women in other cities including Paris, Amsterdam, Montreal, Philadelphia and Fez in Morocco are also writing out catcalls.

'I feel uncomfortable'

Ambrien, 16, started catcalls of Amsterdam.

She says when she was 12 she noticed she was getting more attention from men.

"At first it was just looks and whistling and I didn't think it was a problem, but then I spoke to my sister about it.

"Some people like the attention, which is fine, but I feel uncomfortable. I am not a sexual object," Ambrien adds.

She hopes to expand the account and go to other cities in the Netherlands to write out catcalls.

"I think people aren't talking about it enough in Amsterdam and girls who are 12 or 13 shouldn't be getting unwanted attention from older men."

Image copyright Ambrien Moeniralam Image caption Ambrien started Catcalls of Amsterdam

Some would argue that catcalls are meant as compliments. Farah has an answer for that.

"I've had a lot of people talk to me about the fact that you should be grateful for the attention and it's a compliment, so what's the problem?" she says.

"It's not a compliment to me and I should not have to give my time to you."

As Farah and Sophie talk, a man passing by spots the chalk on the pavement. He thinks it will help to get people talking.

"I have never been catcalled, but my friends have been and it isn't very nice," he says.

"It's not enough that only women are talking about this, I think men need to talk about it too and men should hold their friends and themselves accountable."

Sophie says she has had positive and negative reactions from men.

"Men have said to me: 'This is a good cause, I can't believe men would say that and I didn't know this was happening.'"

She says she's had negative comments too.

"I've had men say: 'Why can't you just take the compliment? This isn't a big deal, move on and get on with your life.'"

'The street should be off-limits'

Sophie and Farah say that now there are other places where men can approach women and there's no need to engage them on the street.

Sophie says: "I find a lot of men that will talk to me have trouble knowing where the line is drawn. When it's harassment and a compliment, or flirting.

"The street isn't the right place. There are bars, dating apps and so many other ways to flirt and court and I think the street should be off-limits."

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