A teenage woman says she was dragged into a public toilet before being slashed and left drenched in blood.
The 18-year-old reportedly 'played dead' to escape the knifeman on Monday evening and ran to a house near to Little Ilford Park, Newham to get help.
She hammered on the front door and begged for help after the attack next to a children's playground.
A family, who had been watching television, took her inside to protect her as she cried: “Help me, I’ve been stabbed, I think I’m going to die," reports the Evening Standard.
One of the family, trained in first aid, grabbed two tea towels to stem the blood as the father called 999.
When police arrived the teenager, who has not been named, was able to whisper a description of her attacker.
She is now in a serious but stable condition in hospital.
One of the family told the Standard: “The paramedics said if it wasn’t for us, she would be dead.”
The father added: “She told us she lay down on the floor and played dead until he left."