"I went over and said, 'That's enough now, leave off.' He tried to stab me but missed. I grabbed him and felt something warm, looked at my sleeve and it was covered in blood. He turned towards me and then Anwar came running, shouting, 'He's got a knife!' and he saved me. We both grabbed him and wrestled him down. The boy was lying there motionless and the other kid was screaming with agony.