A heavy drinker from Birmingham who stabbed a stranger in a phone box after being charged with making a false murder confession has been ordered to be detained in a secure hospital.

Keith Humphreys, of Redditch Road, Kings Norton, was on bail accused of making a hoax 999 call to police investigating the death of a taxi driver when he attacked the innocent member of the public last December.

The 52-year-old was initially arrested after an appeal on the BBC's Crimewatch programme in September last year about the phone call, which was made to detectives probing the murder of Mohammed Arshad.

Wolverhampton Crown Court heard that Humphreys later plunged a knife through the arm of 32-year-old Paul Bettan in nearby Birmingham Road on the evening of December 1 last year.

Prosecutor Stefan Kolodynski told the court that a knife sharpener was found at Humphreys' home after police used CS-spray to disarm him.

The defendant, who was suffering from a psychotic disorder, was found to have committed the wounding by a jury at an earlier hearing.

An additional charge of perverting the course of justice, brought in relation to the hoax call, was dropped because it was not judged to be in the public interest to pursue it.

It is understood that the bogus call was made on August 30 last year from the same phone box at which Mr Bettan was stabbed, suffering injuries which kept him in hospital for three days.

Andrew Davidson, defending, said Humphreys was hallucinating at the time of the stabbing and believed he was being given instructions by a puppet.

Making Humphreys the subject of a hospital order under the Mental Health Act, Judge Nicholas Webb said the victim was very unfortunate to have been "in the wrong place at the wrong time".

Another defendant is awaiting trial charged with the murder of Mr Arshad, who died in hospital in July 2009 after being stabbed in a lane near the border between Birmingham and Worcestershire.