A teenage drug dealer stabbed an unarmed Norfolk security guard to death in a “vicious and brutal attack” after being caught shoplifting a CD, a Norwich court was told today.

A teenage drug dealer stabbed an unarmed Norfolk security guard to death in a “vicious and brutal attack” after being caught shoplifting a CD worth £15.99, a court was told.

Witnesses described the moments after David Watson stabbed 30-year-old Paul Cavanagh in the neck as “like a horror movie” as he ran through the busy Chapelfield Shopping Centre in Norwich covered in blood and wielding a knife.

Watson, of Hackney, east London, who was aged 19 at the time, was stopped by Mr Cavanagh, whose fiancée was pregnant with their first child, for taking a CD from the HMV store in the retail centre in December last year.

Norwich Crown Court heard Watson also stabbed a second security guard Gavin Levett in the shoulder and attempted to slash an off-duty policeman Ian Gardiner who tried to detain him.

Watson denies murder, wounding with intent and attempting to wound with intent.

Prosecutor Graham Parkins QC said Watson was taken to the store's security office after being caught with the CD.

It was here, and after hearing the police had been called, that Watson pulled a kitchen knife from a carrier bag and attempted to escape.

The court heard he later told a prison officer while on remand that he wanted to scare the store security guards into letting him go because he had £10,000 worth of crack cocaine on him and had come to Norwich to “make his money because it was easier up here”.

Mr Parkins said Watson described himself as a “drug dealer”, adding: “He often got angry with bursts of temper, often accompanied by physical violence.”

The prosecutor said Mr Cavanagh, of Rockland St Mary, near Norwich, was simply doing his job. “This was a vicious and brutal attack on an unarmed man,” he said. “He was a wholly innocent man, simply doing his job.”

Watson, now aged 20, originally appeared calm and accepting in the store's office.

The jury of nine men and three women were shown security camera footage showing Mr Cavanagh struggling to restrain Watson.

They also heard from witnesses, including fellow security guard Gary Locke, who was outside taking a phone call when Mr Cavanagh was attacked but came in as Watson ran from the office into the store, busy with Christmas shoppers.

“It was like a horror film, he was covered in blood and had a knife,” he said.

Mr Parkins said it was here he stabbed Mr Levett before running out of the store and into the city, chased by security guards and Mr Gardiner who was shopping in HMV with his girlfriend.

“I remember a commotion at the back of the shop,” said Mr Gardiner who caught up with Watson on a staircase in a nearby car park. He said 'leave me alone' and swung his hand with the knife down towards me,” he said.

Watson briefly got away after Mr Gardiner said he was pushed back down the stairs before he was arrested by police.

The trial continues.