Police said the victim was found in the Nightingale Road area of Edmonton in north London shortly after 1pm on Thursday. She was pronounced dead at the scene.A 25-year-old man has been arrested on suspicion of murder.In a statement, a spokesperson for Scotland Yard said: "On arrival officers discovered a female collapsed in a garden area. A man has been detained and remains in custody."At this very early stage we are not in a position to give further details."Police have added that it is too early to speculate about the motive behind the attack - however it is not believed to be terrorist-related at this stage.A firearms officer suffered a broken wrist in the course of arresting the man.Detective Chief Inspector John Sandlin, who is leading this investigation, said: "This was a highly visible attack in broad daylight on a residential street. I can understand why this may cause people concern, however we are confident that we are not looking for anyone else at this stage."Whilst it is too early to speculate on what the motive behind this attack was I am confident, based on the information currently available to me, that it is not terrorist related."Specialist detectives are expected to remain at the scene in north London for some time.Detective Chief Inspector Sandlin added: "Specially trained family liaison officers will be deployed to support the family; we request that their privacy is respected at this very difficult time."