Amanda Knox has said she is "full of joy" after she and Raffaele Sollecito were acquitted of the murder of British student Meredith Kercher.

Ms Kercher, a 21-year-old from Croydon, South London was sexually assaulted and stabbed to death in Perugia in 2007. Her throat slashed, her body was found under a duvet in a flat she shared with Ms Knox.

Knox and Sollecito were found guilty of her murder in 2009 along with Rudy Guede, a drifter from the Ivory Coast. Guede was sentenced to 16 years at the end of a separate trial and is serving his sentence in Viterbo jail, near Rome.

Italy's Supreme Court overturned the convictions in what is the final ruling in the long-running case. After 10 hours of deliberation, the judges concluded that a conviction could not be supported by the evidence.

Addressing the media at her home in Seattle, a tearful Ms Knox said she was "grateful" following the judgement by Italy's top court.

"I'm still absorbing the present moment, which is full of joy," she said. She added that she was thankful "for the justice I've received and for the support I've had from everyone - from my family, from my friends, to strangers. I'm so grateful to have my life back".

Asked to comment about Ms Kercher, she replied: "Meredith was my friend. She deserved so much in this life. I'm the lucky one."

In contrast, the news was a blow to Ms Kercher's family, who have responded with shock at the judges' ruling.

In a statement they said: "Emotions are naturally raw at this stage. The decision came as a shock but was an outcome we knew was possible, even if it wasn't what we expected.

"We now understand this decision to be definitive and the end of what has been a long and difficult process for all concerned.

"We believe we will learn of the full reasoning behind the decision in the coming months but for now we need some time to take this in and remember Meredith, the victim at the heart of this."

Knox and Sollecito each spent four years in jail for the murder, but were acquitted on appeal in 2011 and then freed after the convictions were overturned. However, their convictions were reinstated by another court in January 2014. They were sentenced to 25 and 28.5 years respectively in jail by the Florence appeals court.

Knox, now 27, returned to the US before an appeal court threw out the acquittal and reinstated the guilty verdicts last year. She said she would not voluntarily return to Italy for the re-trial.

Sollecito and Knox have always maintained their innocence.