Knox prepares final speech to prove her innocence

The legal marathon of the Meredith Kercher murder case enters its last lap this morning when Amanda Knox stands up before two judges, six "lay judges" and hundreds of journalists, to make a final, unscripted speech in her defence. Raffaele Sollecito, her boyfriend, fighting the same verdict, will make a carefully worded statement of his own.

It will be the last chance they have to prove to the court that they had nothing to do with the murder of Ms Kercher, who was Knox's British flatmate. Ahead of his daughter's statement, Curt Knox said: "It's going to be very tough."

He told NBC's Today show: "Amanda is going to be making spontaneous statements and it's going to be very tough to hear her really struggle for her life. She's going to be pleading for her life – that's going to be very difficult to listen to."

If the bench decides to give weight to the opinion of the court-appointed forensic experts, who ruled that the evidence on which Knox and Sollecito were convicted was unreliable, it is possible that the pair could be freed.

But there are many more elements in contention than just forensic evidence – in this case, the clasp of Kercher's bra and a kitchen knife found in Sollecito's flat that the prosecution claimed was the murder weapon.

Above all, there is the persona and character of Knox herself, the object of fierce contention by both sides in the original trial and during the appeal that followed. She admitted that she smoked cannabis on the night the murder was committed and she was said to be casual about hygiene and housework. She had had several lovers since arriving in Italy.

But in the two years since her conviction, Knox has been rehabilitated. As the court heard last week, there was no forensic evidence of her presence in Ms Kercher's bedroom.

Whether the defence has done enough to sway the judges, however, is moot. A lot rides on her final speech.