Despite an impassioned plea from a Levin man facing drugs charges, it took a jury little more than two hours to find him guilty on all counts.

William Duffield McKee, known as Billy, was on trial in Palmerston North District Court this week facing four charges of selling small quantities of cannabis to an undercover policeman, and one of cultivating the drug.

McKee, 47, hosts the GreenCross website, which promotes the use of cannabis to treat medical ailments.

He was targeted in Operation Relief between February 2010 and May last year.

When police searched his house on July 8, 2011, they found 66 cannabis plants.

Representing himself, McKee made a plea to the jury to find him not guilty as a means of pushing for a law change.

Several times he was stopped by Judge Barbara Morris when he tried to talk about the benefits of medicinal cannabis use, with the judge reminding him he could talk only about the evidence.

Outside court, he told the Manawatu Standard he was disappointed with the outcome.

McKee said some laws had been changed through juries returning not guilty verdicts and he had hoped that would be the case in this trial.

‘‘We wanted to have a jury trial because we were trying to make the jury aware of their rights of nullification, where if they think a law is unjust they’ve got a right and obligation to [acquit].’’

In her summing-up, Judge Morris reminded jurors they had to put aside their views on drug use.

‘‘It’s for an elected parliament to make the laws and change the law. It’s for the courts to apply them.’’

Crown prosecutor Andrea Read made a similar pitch.‘‘This trial is not about reforming the cannabis laws in New Zealand,’’ she said.

McKee sold small amounts of cannabis and hemp oil, which is a legal product, to an undercover constable using an assumed name that is suppressed.

The constable said he suffered from migraines and got in touch with McKee through the GreenCross website.

Judge Morris said there were no problems with the police’s undercover tactics. McKee told the jury he felt sorry for the undercover constable and tried to help him.

‘‘He was begging, he was pleading, he was really making me feel bad about what I thought was a potential brain tumour coming on,’’ McKee said.

He said he used cannabis to reduce the effects of post traumatic stress disorder and nerve damage to his amputated right leg.

He has been remanded on bail until sentencing next month.