A dentist who thought he was possessed by evil spirits fatally stabbed a faith healer at an east London clinic which claims to treat black magic.

Zakariyya Islam was knifed in the stomach and heart with a 25cm blade by Ashfaq Choudhry on September 14 last year.

A witness reported hearing a disturbance at the Ruqya Therapy Centre in Greatorex Street, Whitechapel, before Mr Islam appeared and said “Call the police, somebody stabbed me”.

The 45-year-old, who was a member of East London Mosque, died about 30 minutes later.

Choudhry, 43, of Kensington Avenue, Watford, was arrested after attempting to jump into the moat at the Tower of London and he confessed to officers he had stabbed someone.

The father-of-two, who was suffering from a severe mental illness, later pleaded guilty at the Old Bailey to manslaughter on the grounds of diminished responsibility.

Prosecutor Timothy Cray told the court Choudhry’s mental illness affected his ability to form a rational judgement and to exercise self-control.

The defendant, who had told psychiatrists he felt "worthless", became disillusioned with the medication he was on and decided to explore alternative therapies, the court heard.

Choudhry visited Mr Islam at the centre, which the court heard practices a form of spiritual therapy, three weeks before the killing, and said he was told he was possessed by spirits.

Linda Strudwick, mitigating, said: “[Choudhry] genuinely believed what he had been told, that somebody had put evil spirits into him."

After his visit to the clinic Ms Strudwick said he told others: "Look at me, look at me, I'm a monster."

Sentencing Choudhry, judge Richard Marks QC, the Common Serjeant of London, said Mr Islam, had been well-intentioned in his words and actions.

He added: "There is no doubt that [Mr Islam] was doing what he genuinely thought was best in order to alleviate your symptoms."

Choudhry was given a hospital order under the Mental Health Act, without a time limit.

Additional reporting by Press Association.