A High Court judge has ordered Northcote College to reinstate a special needs student who was expelled after telling the principal he had smoked cannabis at a shopping mall after school.

The college is unrepentant, insisting it had the jurisdiction to expel the first-time offender despite the incident's happening outside school hours and while the boy was only partially clad in school uniform.

Principal Ted Benton yesterday called the decision a "sad day for New Zealand" and vowed to continue his hard line on drugs.

"I'd do the same again tomorrow. We've got to draw the line somewhere.

"If the rest of society wants to go soft, I can tell you that secondary schools are not going to," he told the Weekend Herald.

In the High Court at Auckland yesterday, Justice David Baragwanath quashed the board of trustees' March expulsion decision and ordered that the fifth-former be able to resume his schooling immediately and that the trustees pay his $7495 legal bill.

The 16-year-old's family had received legal aid and were represented by a Queen's Counsel, Dr Rodney Harrison.

Justice Baragwanath suppressed the boy's name.

Although he did not rule the expulsion unlawful, he said at a previous hearing that he was "deeply concerned" at what appeared to be a breach of the Education Act requirement that principals try to arrange alternative schooling for excluded students.

The boy, 15 at the time but with the intellectual capacity of an 11-year-old, smoked cannabis with two friends in the carpark of the Birkenhead shops about 5.30 pm on March 21.

He was wearing the school's blue trousers but his top was not school-issue.

The next day two third-formers were caught smoking cannabis in the school and because the boy was seen nearby, he was called into Mr Benton's office for questioning.

Although he was not involved, he voluntarily admitted to Mr Benton the previous day's incident. He was suspended and, after a hearing before the board of trustees' disciplinary subcommittee, expelled from the school.

The two third-formers were reinstated.

The Weekend Herald has learned that Mr Benton had initially recommended to the subcommittee that the boy be given a second chance and be allowed to return to school.

But the principal said yesterday that he fully supported the board's decision and was against allowing the boy back.

Now that the High Court had ordered the boy's return, he would get a "fresh start".

Mr Benton said the school had decided not to defend itself in court for monetary reasons.

He said the two third-formers were reinstated because school policy allowed junior students who were first offenders to return to school as long as they returned clear drug tests and underwent counselling.

Dr Harrison said yesterday that he did not understand why Mr Benton was taking his tough line when he had earlier recommended that the boy be given a second chance.

"Drugs in schools is not the issue in this case. The issue is whether the college had correctly followed mandatory legal procedures."

A spokesman for the Schools Trustees Association, Chris France, said the case showed that school boards had to be extremely careful that disciplinary cases were handled correctly to prevent legal action being taken.