Meredith killer 'will prove her innocence'

The student was found guilty along with Italian former boyfriend Raffaele Sollecito in December of killing exchange student Miss Kercher but said she will "fight to prove" she is innocent.

She also revealed she exchanges letters with 26-year-old Sollecito, who is held in a different prison. Knox, 23, said: "We often write to each other, we give each other strength.

"We have ended up in a surreal affair that we still don't understand but at least it unites us. The affection remains from the love we had."

In an interview with Italian magazine Oggi, Knox described her prison routine, saying she gets up at around 6am and does yoga before replying to the 300 letters she receives each month from family and supporters.

She is continuing her Washington University degree in Italian and creative writing via a correspondence course and often spends the afternoons studying and playing volleyball with other inmates.

She insisted she was not involved in Miss Kercher's murder, adding: "I find it really hard to accept that my friend Meredith is dead, and I am accused of killing her. It's really hard for me and, at times, the whole thing is much bigger than me."

Miss Kercher, 21, from Coulsdon, Surrey, was found dead in her bedroom in Perugia on November 2, 2007, in the house she shared with Knox and others in the Umbrian town.

Knox, from Seattle, was jailed for 26 years while Sollecito was sentenced to 25 years. A third defendant, Rudy Hermann Guede, an immigrant from the Ivory Coast, was convicted of Miss Kercher's murder in a separate trial.