Clara Corrigan is recovering from 17 wounds inflicted in the attack, which took place about 30 miles from Praia da Luz, where Madeleine disappeared.
Clara told her family from hospital: “When he made that threat I was absolutely terrified. I knew my life was in danger.”
Now Clara, 39, from Liverpool, has said she would be willing to talk to Scotland Yard detectives who have just overseen a huge search operation on wasteland in Praia da Luz which failed to find any trace of Madeleine.
The little girl disappeared from her family’s holiday apartment on May 3, 2007, days before her fourth birthday.
Clara told her father John: “I’m surprised the detectives have not come to see me because I could have important information.”
John said: “She was in a shocking state, terrible.
She told the Portuguese police that and she was expecting to hear from Scotland Yard but so far no one has contacted her
John Corrigan, Clara's father
"She said she got really terrified when he said he had killed Madeleine McCann. She told the Portuguese police that and she was expecting to hear from Scotland Yard but so far no one has contacted her.”
Scotland Yard would not say if they were aware of her claims. The man Clara says stabbed her is Briton Shane Leighton, who is being held in a prison on the Algarve. She was attacked in Albufeira on May 28 after she met trainee chef Leighton who was celebrating his 22nd birthday.
Clara, a single mother of three, told Portuguese police that he invited her to his family home in the resort town where he was throwing a late-night birthday party. However, when she got to the terraced villa there was no party.
Clara, who fell asleep, said: “I woke up with him on top of me, suffocating me. Then he shouted ‘I killed Madeleine McCann and I am going to kill you’.”
She was stabbed up to 17 times on her buttocks and lower back.
Clara was taken to hospital for emergency treatment for loss of blood and to have her wounds stitched. She has since returned to Liverpool.