Charities have sparked a backlash over the use of NDAslinked to ‘Sarah’s Law’ after a woman who outed her paedophile neighbour was taken to court for revealing his crimes.
It allows anyone to ask their local police force if someone has a record of committing crimes against children.
Such disclosures have nearly doubled since the law was introduced in 2011, rising from 120 a year to 219 annually, according to figures obtained under Freedom of Information (FoI) laws.
The data, submitted by the Portsmouth University's journalism department, revealed that of the 46 forces in the UK, 22 returned comparable data, revealing at least 1,140 disclosures have been made to parents since 2011.
However, experts warn that the true figure could be much higher, with at least 1,427 adults informed someone close to their child has a history of sexual offences since 2011.
This comes following a high-profile case in which a mother-of-two was taken to court after using the scheme to discover she had a paedophile neighbour in 2017. She was made to sign a Non-Disclosure Agreement, but subsequently outed him.
Claire Varin became suspicious of a new neighbour after he knocked on their door and asked if their eight-year-old daughter would like to go berry picking with him.
After becoming suspicious, she contacted West Yorkshire police and discovered he had previously been jailed for possessing child abuse images.
Under the conditions of Sarah's Law, Ms Varin, a 37-year-old carer, was made to sign a non-disclosure form, preventing her from warning anybody else. However, after her neighbours found out, she was taken to court.
"It makes you question how effective the law is,” she said. “It's meant to be there to protect children, but we can't share the information - technically you aren't even supposed to tell your partner, although the police did accept I was going to do so to protect my children."
The charges were eventually dropped, but following the ordeal, Ms Varin separated from her partner and moved away from the street she lived on.
She said: "We were just left to deal with this information. We were told a paedophile had moved onto the street and we were expected to just live with it.
"The person who is disclosed to, how can you sit back and just watch them interact with children? You are just as bad then, it is on your conscience."
"The stress of it all meant I didn't want to live there anymore. He refused to move out until just a few months ago. All I had done was what anyone else would have done."
Applications under Sarah's Law can be made by anyone, but the police will only inform the person who is able to protect the child.
Following publication of the latest figures, which reveal that increasing numbers of parents have been told by police that an individual with access to their child or children is a sex offender, experts have warned that the current law does not go far enough to protect children.
Even if an application does not result in a disclosure, those who enquired are given a pack with information about where to turn if they suspect abuse.
Donald Findlater, director of child abuse helpline Stop It Now!, said it was "reassuring" to see the figures growing.
"I would like to see this trend continue because it is demonstrating awareness and vigilance,” he said.
"If a disclosure is not made, that is not saying to someone 'you don't need to be concerned', because they might have a concern that is a legitimate one, he just hasn't been arrested for something yet.”
"Right now there are approximately 59,000 people on the sex offender register, but that is simply a fraction of those who represent a risk to children. Just telling a parent, 'this person is not on the register' is not telling people not to worry."
From the year the law was introduced to the last financial year, 8,958 applications were made by members of the public based on 22 police forces who supplied comparable data.
However, incomplete data from other forces suggests the total number of applications from across this period was at least as high as 16,900.
The proportion of applications that resulted in disclosure remained the same, at 14%, in both 2011/12 and 2018/19.
For the last three financial years, 28 forces returned comparable figures which show a 29% increase in applications over this period and a 57% increase in disclosures.
Sophie Humphreys OBE, child protection expert, said: “Sharing information of this nature is complex and help must to be provided to the people they disclose it to in a supportive way that reassures them that appropriate action will be taken to ensure they do not present a risk to children.
“Developing positive relationships between professionals and communities with clear but sensitive communication is what will keep children safe ideally rather than legal action.”
She added that people on the sex offenders register would be contravening the terms of their licence by attempting to contact a child.