A registered sex offender who groomed a 14-year-old girl before repeatedly sexually assaulting her has been jailed.

Predator Gary Cawthorne, 53, from Greenhithe, used the alias Lee Mason and contacted his vulnerable victim, promising her a job.

They met up a number of times and during these meetings, Cawthorne sexually assaulted her.

Their encounters came to light after the victim's schoolfriend found messages on her phone from him and got in contact.

He requested a photo of her and she sent a head shot. He then asked for a photo of her body, prompting her to tell her parents who contacted her school.

The school alerted police on Monday, February 29 and both girls were spoken to by officers from the Met Police's sexual offences exploitation and child abuse department the following day.

"He has shown himself to be manipulative and relentless in pursuing his young victims" - NSPCC

An investigation was launched and Lee Mason was identified as Gary Cawthorne through the phone number he used to contact both girls.

He was already on the sex offenders' register at the time after sexually assaulting a 16-year-old girl.

He was arrested on Wednesday, March 2, for questioning and further arrested on Thursday, March 5, which saw him charged later that day.

He later admitted two counts of sexual assault on a child under 16, one count of grooming and breaching a sexual harm prevention order (SHPO) at Southwark Crown Court.

He was jailed for a total of four years and five months. Cawthorne will also be subject to a SHPO for life and made to sign the sex offenders' register indefinitely.

Detective Constable Tony Foran said: "Cawthorne is a known sex offender and is a danger to children - he has now been jailed for his offences.

"He pursued the 14-year-old girl by phone and in person. Then he sexually assaulted her.

"The victim's friend became suspicious of his contact and thanks to her brave actions she was able to flag up his activities to her parents who then alerted the authorities."

An NSPCC spokesperson added: "Gary Cawthorne was already a registered sex offender. His deplorable actions show a complete disregard for the law and the devastating impact those actions have.

"He has shown himself to be manipulative and relentless in pursuing his young victims.

"It is imperative he undergoes treatment while he serves his sentence to ensure he does not re-offend on his release.

"Anyone worried about a child can contact our helpline free and in confidence on 0808 800 5000. Children can call ChildLine on 0800 1111."