Laudat approached Bryan Bennett, 56, at a day centre in Stratford, east London, last July, and "coldly and clinically" stabbed him from behind, said John Bevan, for the prosecution.
Mr Bennett screamed, rolled up in a ball and tried to hide but Laudat continued to rain blows on him, threatening others in the room, who fled. Fifteen minutes later Inspector Keith Topliss arrived after an emergency call. Armed only with a 4ft plant pole he went into the room, where Laudat was kneeling by Mr Bennett's body and still stabbing him.
The officer told Laudat: "Listen carefully. Move away from there and put the knife on the floor." He obeyed. Insp Topliss said after the hearing: "I hope I never see anything like it again. I was in shock for days. I was astonished that he just stopped when I told him to."
After the killing Laudat said he thought he was doing "a public service" by stabbing Ronnie Kray. Laudat, who lived with his mother in Stratford, denied murder but admitted manslaughter on the grounds of diminished responsibility.
The court heard that he had suffered from mental illness since 1989. He was jailed for four years for knife-point robberies in 1991. He was transferred to hospital and discharged in December last year when his sentence expired.
At that time Laudat was refusing to take medication. On his discharge he agreed to after-care by the local social services.
He and Mr Bennett both attended the day centre. Mr Bennett, who had a broken marriage, was described as gentle and harmless.Reuse content