The case, involving tobacco companies RJR MacDonald and Imperial Tobacco, was heard in Quebec.

In July, 1991, the judge ruled that commercial speech was protected, so the government's move to ban tobacco advertising, given that it could not provide evidence to prove it was harmful to health, was unconstitutional.

However, an appeal by the government resulted in an Appeal Court decision last Friday to reverse the judgement, on a two-to-one vote by three judges.

The decision means that so far, two judges have found for the plaintiff tobacco companies and two against.

Before the appeal it was possible to say that only one judge had found the ban unconstitutional.

But now that two have come to the same conclusion, it has established that there is a genuine difference of legal opinion on the issue.

It is understood that the tobacco companies have applied for leave to appeal to the Supreme Court in an attempt to restore the original decision.

They want to prevent the banning of tobacco advertising on the grounds that it is unconstitutional.

Opinions are divided as to whether this recent judgement will affect Hongkong, which is awaiting the Government's decision over a potential tobacco advertising ban.

The issue here is complex.

A ban on all tobacco advertising would remove it from printed material and outdoor sites in the territory.

It was banned from television and radio in December, 1990.

Legislation would also disallow any association with cigarette brand names for sports or other events, or products bearing a tobacco manufacturer's brand name.

This would put in jeopardy championship tennis tournaments such as the Marlboro Tennis Championships.

It also opens up a can of worms over products bearing tobacco manufacturers' names.

For instance, Dunhill makes clothes and accessories as well as cigarettes.

So do Cartier, Yves St Laurent and Marlboro.

The proposed legislation suggests that they will no longer be allowed to advertise these alternative products, or be forced to discontinue their manufacture altogether.

More importantly, in the run-up to 1997 any judgement threatening freedom of speech in Hongkong is serious.

Will the reversal of judgement in Canada affect Hongkong? ''From a local point of view the Canadian decision is unfortunate because it means we are looking at a precedent,'' said Mr Robert Fletcher, regional public affairs manager for Rothmans (Far East) and chairman of Hongkong's Tobacco Institute.

''However, it probably will not impact here, although it is a bit of a blow because the principles involved are similar,'' he said.

What is slightly more encouraging for the advertising, marketing and tobacco industries in Hongkong is that Article 16 of the Bill of Rights, under which freedom of speech is protected, affords slightly stronger protection than that which exists in Canada.

In Canada, the law says that everyone has freedom of expression including the press and other media.

Hongkong's law states that everyone has the right to freedom of expression including freedom to seek, receive and impart information of all kinds, through any media.

Effectively, the language of Hongkong's freedom is wider and more generous.

''The Hongkong Government will have to take the Bill of Rights seriously in terms of its proposed intention to restrict media and advertising,'' said Mr David Shannon, partner at international law firm Baker & McKenzie.

''Article 16 protects the freedom of advertising and that is a freedom which has been reaffirmed by the Canadian case.

''It says the point has got to be taken more seriously.

''An argument that persuaded one other judge must have merit in it,'' he said.

The International Advertising Association (IAA) Hongkong Chapter chairman, Mr John Dollisson, agreed that the decision could be useful for Hongkong as it kept the debate open.

''For us, it proves that this issue of banning tobacco advertising is a debatable point and is far from being a closed book, so it is helpful to our argument opposing the ban in that respect,'' he said.