A paranoid schizophrenic, who stabbed a police officer to death, had earlier threatened to kill a carpenter who had been sent to fix his fence, a jury heard yesterday.

Glaister Earl Butler emerged from his house with a 14-inch kitchen knife, shouting threats that he was going to decapitate and kill Michael John Wood.

Mr Wood told Birmingham Crown Court he managed to keep the 49-year-old at a distance with a metal bar he was using to smash up concrete around the gatepost.

He then alerted police to the incident, which happened outside Butler's council flat in Long Acre, Nechells, Birmingham, on May 21 last year.

Butler later stabbed Detective Constable Michael Swindells to death after officers were sent to investigate.

He denies murdering the 44-year-old father-of-two, from Burton-upon-Trent, Staffordshire, but admits manslaughter due to diminished responsibility.

Giving evidence, Mr Wood, who works for a firm of subcontractors for Birmingham City Council, said Butler confronted him with the knife, which had been sharpened into a point, and said he was holding the weapon at about chin height.

"He was threatening to cut my head off, kill me," he told the jury.

"As he got to me, I sort of stumbled across the hole and grabbed the iron bar and put it between us."

Mr Wood said Butler appeared to be "put off" by the iron bar and returned to his house, still issuing threats and swearing.

"I was quite calm. I kept talking to him very loudly, saying I was just here to help and put a new gate on. I kept repeating I was supposed to be here and... he shouldn't be upset with me," he added.

"If he'd got that much closer, he would have done it."

Mr Wood told police he thought his threats to kill were serious and remarked to his wife later that he even thought he was capable of killing any officers sent to arrest him.

The confrontation between Butler and Mr Wood was witnessed by the defendant's neighbour, Iris Rose.

She told detectives he was a noisy neighbour who banged doors constantly, causing their dog to bark, and talked to himself.

The trial continues.