A DRUGS expert yesterday told a court he doubted claims by a schoolboy accused of murder that he was smoking about 300 cannabis joints a week.

Detective Constable Brian Melrose said he had never heard of anyone using such a large amount of the drug after Luke Mitchell, 16, told a psychiatrist he was smoking 2oz of the drug a week around the time of the death of Jodi Jones - the equivalent of 40 joints a day, or nearly 300 perweek.

Mr Mitchell, then 14, also claimed that the amount doubled to 4oz after Jodi's death.

Mr Melrose, a drugs expert, told the High Court in Edinburgh that a 2oz-a-week habit would make around 300 joints, and cost a user around Pounds90.

He said: "Even as an adult it would be difficult to function on that amount."

Mr Mitchell denies murdering Jodi with a knife or similar instrument. He claims that at the time he was in, or near, his home at Newbattle Abbey Crescent, Dalkeith, and that Jodi was murdered by person or persons unknown.

The court was told that when Mr Mitchell, then 15, was arrested last year and charged with murdering the 14-yearold, police also searched his home in Dalkeith, Midlothian.

They found a piece of cannabis resin in his trousers pocket and two other smaller pieces.

Mr Mitchell claims the drugs were for his own personal use.

He also told police he had bought the cannabis for Pounds150.

"Cheap, but not outwith the bounds of possibility, "Mr Melrose told Alan Turnbull QC, prosecuting.

The court heard that a user might add cannabis resin to tobacco to make a reefer cigarette.

When asked how much might come from Mr Mitchell's cannabis, Mr Melrose said:

"You are looking at nearly 500 reefer cigarettes."

A drug user might smoke three or four, perhaps five such joints a day, he added.

The lawyer asked: "And following the death of Jodi Jones, Luke Mitchell's use of cannabis escalated considerably?"

The detective replied he had never heard of anyone using that much.

Later, the court was told how the accused and the schoolgirl "really, really loved each other".

In a police statement, Laura Wightman, Jodi's best friend, described howMrMitchell was affectionate to his girlfriend, and often hugged her in public.

However, the 15-year-old said she had criticised Mr Mitchell when he bought a knife after Jodi's death.

Passages from statements she gave to police in July 2003 and in Septemberwere read in court after the jury was told the girl was too ill to give evidence.

She described herself as really close to Jodi and also "best mates"with Luke.

"They really, really loved each other. They were always hugging and stuff, which was cool because most guys won't do that in front of people, " she said.

However, she also described how she "went radge" when she discovered Mr Mitchell was buying a lock-knife some time after Jodi's death.

"I told him it was really disrespectful, " she said. Mr Mitchell, she claimed, replied:

"It is only for cutting weed."

The detectives asked her in September if Mr Mitchell had ever done or said anything to make her suspect he had been involved in Jodi's death. Laura told them: "No, I would - see - if he did tell me I would have killed him there and then and it would have been me sitting in the jail now."

She added: "I think he is innocent."

The trial continues.