The Court held last month that the absence of immunity will create “a more flexible legal system with a greater capacity to deliver justice in the individual case”.

Unanimous in their decision to dismiss the appeal in Chamberlains v Lai, the Court upheld the Court of Appeal judgment striking out the defence of immunity, but decided against leaving immunity for criminal proceedings for another day.

In the principal judgment delivered by the Court, it was held: “A distinction for the purposes of immunity between advocates conducting criminal proceedings and advocates conducting civil proceedings would be invidious for the reasons given in [Arthur J S Hall v Simons]. And the incongruity would be exacerbated by the difficulties of classification of proceedings as civil or criminal”.

The Court concluded that the reasons traditionally given for immunity are no longer justified.

“The former principal justifications for the immunity no longer persuade, if they ever did,” the judgment said.

It was also argued: “Although consistency with Australian law may have been a more important consideration if the matter had been evenly balanced, we consider that the answer as a matter of New Zealand law is clear-cut”.

The Court did not agree that any reconsideration of immunity should be left to Parliament. “The immunity was a creation of the common law. Its reception into New Zealand law did not alter its character.”

In response to the decision, Jim Farmer QC, president of the New Zealand Bar Association, said the Court’s judgments created more problems than they solved.

While the abolition of barristerial immunity now leaves barristers vulnerable to negligence claims, Farmer said, a claim brought against a barrister may end up being struck out by the court as an abuse of process, which will just amount to good money being thrown after bad. He did not think it was in the public interest that people should be encouraged to take cases that by their very nature were most unlikely to have realistic prospects of success.

However, Robert Gapes, Simpson Grierson partner and counsel for Hilda Lai, said the decision would help protect ordinary litigants against miscarriages of justice caused by their lawyer’s negligence.

“Those litigation lawyers who feel threatened can take some comfort from the experience in England where barristers immunity was abolished by the House of Lords in 2000,” Gapes said.