Italian prosecutors demanded life sentences yesterday for Amanda Knox and Raffaele Sollecito, her former boyfriend, for murdering the British student Meredith Kercher in a hate-and drug-fuelled sexual assault.

They are accused of sexually abusing and killing Kercher, 21, from Coulsdon, Surrey, whose body was found in the cottage she and Knox shared in Perugia two years ago.

Knox, 22, from Seattle, told the court the accusations against her were “fantasy”.

Manuela Comodi, the deputy prosecutor, said, however, that DNA and other evidence linking the accused to the crime was “irrefutable and well corroborated”.

The evidence includes a kitchen knife found at Sollecito’s flat that forensic officers said had Knox’s DNA on the handle and Kercher’s on the blade — a finding disputed by the accused.

Summing up his case on Friday, Giuliano Mignini, the chief prosecutor, described Kercher as the victim of “an unstoppable crescendo of violence” committed by three “frenzied furies” — Knox, Sollecito, a 25-year-old IT graduate from southern Italy, and Rudy Guede, an immigrant from Ivory Coast who has already been convicted of the murder.

Knox cried discreetly, head bowed and almost immobile, as Mignini continued: “For Amanda, the time had come to seek revenge on ‘that simpering girl’.”

He asserted that, acting under “the fumes of drugs and possibly alcohol” and prompted by hatred for Kercher, Knox got into a row over money with the victim and led Sollecito into an assault.

He asserted that Knox dealt the first blow, pushing Kercher’s head against the wall. Knox then tried to strangle her and strike her with a knife, he said.

Mignini said it was easy to imagine that Knox told Kercher: “You acted the goody-goody so much, now we’re going to show you. Now you’re going to be forced to have sex.”

The attackers tried to strip Kercher, pulling off her jeans, Mignini argued. Guede sexually assaulted her and then, using two knives, Knox and Sollecito stabbed her in the neck — with Knox inflicting the fatal wound.

The two men took part in the attack “because between the two there was a competition to please Knox”, Mignini said. After Kercher died, the killers faked a burglary, breaking a window in the room of a flatmate.

In response, Knox told the court: “Meredith was my friend ... I didn’t hate her. It’s absurd to say that I wanted to seek revenge against a friend who was very nice to me. What I’ve heard in the last two days is pure fantasy, it’s not reality.”

A verdict is expected on December 5.

Times Recommends

• Patty Hearst, the SLA and me
• Palin caught with crib notes scrawled on hand
• Hugo Chávez takes to the airwaves – 24/7