A serial sex offender has been jailed for 24 years for repeatedly raping a young mother in a "vicious and prolonged" attack as her children slept in the next room.

Pierre Antoine Bate, 42, broke into the victim's Thornton Heath home in the early hours of the morning in July 1996 and threatened to harm her children if she screamed for help.

The Californian, from Santa Barbara, then proceeded to rape the woman eight times over the course of 90 minutes, tying her up when she tried to escape.

Sentencing Bate today at Southwark Crown Court, Judge Jeffrey Pegden said the crimes were of "exceptional gravity" and had "absolutely ruined" the victim's life.

Bate, who was found guilty last month of eight counts of rape and one count of burglary with intent to rape following a two-week trial, shook his head as the judge recounted the horrific details of his offences.

The American was extradited from the US in February this year after Metropolitan Police cold-case investigators used modern DNA testing to link him to the crime.

Bate had already been extradited back to the UK in 2008 for trial following a 2004 cold-case investigation into a sex offence committed in Kentish Town in October 1995 - just two months after Bates's arrival in the UK.

On that occasion, Bate had climbed into a young woman's bedroom and lay on top of her masturbating as she slept, before the victim woke in horror and screamed for help, the court heard today.

He served 26 months in jail for that offence before returning to the US, and it was DNA samples taken following that incident that led detectives to link him to the Thornton Heath rape.

Judge Pegden said a "significant degree of planning" had gone into the attack in Thornton Heath, which Bate committed when he was 22.

The judge said: "It was plain to me that you had been watching the victim in the weeks before these offences.

"You stalked your victim as a sexual predator...awaiting your opportunity to have your way with her in the depths of the night."

Bate had even broke into the victim's house prior to the attack and left a knife by her bed in a "bizarre prelude to these offences", Judge Pegden said.

Before the judge handed down his sentence, Bate, wearing a grey sweater, claimed his treatment at the hands of the British justice system had been "despicable".

He was representing himself at the sentencing after parting company with his legal team during the trial, the judge said.

Just after 1am on July 22, 1996, the victim woke up to find Bate, a complete stranger who had broken in through a first floor window, in her bedroom staring at her.

To control her he claimed a friend of his was with her children in the room next door, before raping her.

During the attack, the woman "believed you were going to strangle and kill her", Judge Pegden said.

He added: "[Her children] could have walked in at any time to see their mother suffering a violent sexual attack."

Their mother's life had been "completely ruined", the judge said, adding: "You were responsible for the most extreme harm and extreme consequences...

"You completely ruined the life of that young woman for your bizarre predatory sexual pleasures.

"She has been quite unable to have any relationship for the last 20 years."

Speaking last month following Bate's conviction, detective sergeant Karen Bradley, of the Met’s sexual offences, exploitation and child abuse command, said: "Thanks to developments in forensics and our commitment to identify and arrest people no matter how much time has passed, Bate is today facing a long time in prison.

“He had thought that he wouldn't get caught, despite moving to the US we brought him back to London to face justice.

“He is a dangerous man, who broke into the house that night with the sole intention of committing rape.

"The victim has shown huge courage in supporting our investigation and the court case, after a vicious and prolonged attack in her home with her children asleep close by."