Revenge porn
Revenge porn has been made illegal in California (Reuters) Reuters

Revenge porn, where ex-partners post sexually explicit pictures of their former loved-ones online, is on the increase in the UK.

As yet there is no UK law under which offenders who post images without people's consent can be prosecuted, unlike in the US.

Revenge porn legislation has been introduced in states such as California, Texas and this week in Utah with politicians in New York state campaigning for similar measures.

What we're getting is just the tip of the iceberg
- Laura Higgins, UK Safer Internet Centre

Now the UK's leading online support groups - The National Stalking Helpline, Women's Aid and the UK Safer Internet Centre - say the problem is escalating in this country and are campaigning to adopt the US example.

At the moment only certain privacy and harassment laws can be applied if a person has committed more than one offence against their ex-partner.

But it depends on the courts and the local police whether they have had much experience in dealing with revenge porn cases, according to Laura Higgins, a helpline manager at the UK Safer Internet Centre.

"There is legislation here in the UK but I don't think it's very co-ordinated," she said.

She said her organisation has observed a large rise in calls from complaints of revenge porn victims over the past 12 months.

She told BBC Newsbeat: "What we're getting is just the tip of the iceberg. So many people are simply too embarrassed and humiliated to seek help or advice."

Heather Robertson, a law student at York University, has started an online petition for laws to recognise revenge porn as a sexual crime after her friend became a victim. The petition has already gained more than 2,000 signatures.

A recent landmark case in the US involved Kevin Bollaert, 27, of San Diego, was accused of uploading more than 10,000 sexually explicit photos of men and women to his website ugotposted.com.

Pictures and the victim's name, age, location, and a link to their Facebook profile were all posted online. They then had to pay up to $350 on a second site, called changemyreputation.com to get the pictures removed. He could face imprisonment if found guilty. Both sites have since been deactivated.

Anisha Vora's ex-boyfriend was jailed for six months in New Jersey earlier this year after he posted sexually explicit photos of her on several websites.

"I went from three sites to over 200. My ex was putting my address out, my phone number," said the 24-year-old. "I stopped going to school for a year and a half. I was afraid to leave my house.

"I had known him for more than 10 years. It wasn't a nasty break-up we just went our own separate ways. I never thought he would post the photos."

Carrie Goldberg, who is based in Brooklyn, started her practice in January 2014 to specifically deal with revenge porn cases.

"The response was immediate and unexpected," she said. "I'm getting calls daily from victims. Their ages range from as young as 13 to as old as 40."

She added: "Sexting images is not exceptional behaviour anymore. It's really, really common to take and send sexual images and it means more people are going to need protection from the law."

Hunter Moore, 27, dubbed 'the most hated man on the internet', avoided prosecution for running IsAnyoneUp.com, which he created in 2010.

The site was visited by as many as 350,000 users a day and earned him tens of thousands of dollars before he sold it to anti-bullying charity Bullyville. He described himself as a 'professional life ruiner' and taunted his victims, telling one: "We've all masturbated to you. It can't get any worse."