Nearly 500 online child sex crimes took place on Facebook apps in the East of England last year, the NSPCC has said.

And the charity is worried that figure could rise if Facebook introduces end-to-end encryption in its apps.

According to Freedom of Information requests from 32 police forces in the UK, the NSPCC found the region had 482 cases of child sex crimes recorded with Facebook apps between 2018-19.

Of the recorded instances, which include child abuse image sharing and online sexual offences, 162 occurred on Facebook, while 288 happened on Instagram and 32 on Whatsapp.

In Hertfordshire, the data found there were a total of 94 child sex offences online between 2018-19, 40 of which were through Facebook apps.

Nationally, out of 9,259 instances where police in England and Wales said they know the platform used in child abuse image and online child sexual offences, just over 4,000 were carried out on Facebook, Instagram or WhatsApp.

Only three per cent (299 instances) were from WhatsApp, which the NSPCC says highlights how difficult it becomes to detect crimes on an end-to-end encrypted platform.

The charity believes criminals will be able to carry out more serious child abuse on Facebook's apps undetected without needing to lure them off to encrypted platforms, if it goes ahead with changes.

"Instead of working to protect children and make the online world they live in safer, Facebook is actively choosing to give offenders a place to hide in the shadows and risks making itself a one-stop grooming shop," said Andy Burrows, NSPCC's head of child safety online policy.

"For far too long, Facebook's mantra has been to move fast and break things but these figures provide a clear snapshot of the thousands of child sex crimes that could go undetected if they push ahead with their plans unchecked.

"If Facebook fails to guarantee encryption won't be detrimental to children's safety, the next Government must make clear they will face tough consequences from day one for breaching their duty of care."

The NSPCC is calling for supporters to sign an open letter to Facebook, proposing measures such as no end-to-end encryption for messages going to or coming from children's accounts.

The charity also wants adults' accounts not to be encrypted until and unless Facebook has solutions to ensure child abuse can be detected and that children's safety will not be compromised.

Heightened concerns come after the Home Secretary Priti Patel and her counterparts in the US and Australia wrote to Facebook chief Mark Zuckerberg, explaining how such a move could hinder law enforcement trying to investigate child abusers and terrorists operating online.

A Facebook spokesman responded, saying: "There is no place for grooming or child exploitation on our platforms.

"We use technology to proactively remove it and are developing further ways to detect patterns of harmful behaviour in order to ban and report those responsible.

"We work closely with child protection authorities in the UK, and we're consulting with experts on the best ways to implement safety measures before fully implementing end-to-end encryption."