A serial rapist who committed a string of violent and depraved sex assaults after being freed from prison on licence has been jailed for life.

Daniel Elliott, 24, subjected three victims - including girls as young as 15 and 16 - to "unimaginable" horror after being released from his prison for the rape of a Japanese student he attacked in 2010.

Within months of being freed, Elliott had committed two rapes and several other offences in a string terrifying sex attacks.

In the first of three separate attacks, he grabbed a 28-year-old woman round the neck from behind as she walked along a footpath in Wallington, south-west London, on the night of August 3 last year. He threatened to stab the woman before sexually assaulting her and fleeing the scene, police said.

Around a month later, Elliott struck again, threatening a 16-year-old girl and her boyfriend of the same age with pepper spray as they walked down Church Path in Chiswick.

The attacker forced the pair to the ground and held a tin can to the victim's eyes as he sexually assaulted and then raped her.

In November last year, Elliott launched another horrifying assault after approaching a 17-year-old boy and his 15-year-old girlfriend in a fenced children's playground in Carshalton.

He punched the boy in the face and dragged him to the ground before threatening to stab him and calling over the girl. The sick attacker then digitally penetrated and tried to rape her.

When she resisted, he threatened to stab the boy, before proceeding to orally raping her and fleeing the scene.

Elliott, 24, of, Rosewell Close, Penge, had previously been jailed in 2010 for raping a 19-year-old Japanese student who had only been in the UK for two days. He had preyed on the vulnerable victim after she became separated from friends, police said.

He was convicted on May 21 at Southwark Crown Court of two counts of rape, one count of attempted rape, one count of digital penetration and one count of sexual touching on 21 May.

Today, he was jailed for life at the same court.

Detective Inspector Keith Ward, of the Metropolitan Police's Sexual Offences, Exploitation and Child Abuse Command, said: "These were planned, targeted and violent stranger rapes. Elliott is clearly an extremely ruthless, predatory and dangerous man.

"This prosecution would not have been possible without the courage of the victims who were willing to support proceedings. The physical and emotional impact on them of the abhorrent actions of Elliott are impossible to quantify.

"The victims have been subjected to a nightmare of unimaginable proportions and I praise them for their exceptional bravery. I hope that the conviction and today's sentence will offer them some comfort. Our thoughts are very much with them at this time.

"I am very pleased that Elliott will be off the streets for such a long time. He is a danger to the public and the sentence the judge has handed down that fits the horrific crimes he committed."