LONDON – A U.K. court of appeals ruled in favor of the country’s mandatory plain packaging rule for cigarettes, The Guardian reports. The ruling this week is a blow to the legal challenges to the plain packaging regulation, which stipulates that cigarette packs must be indistinguishable from other brands with a bland typeface, size and color.

In May, the high court ruled against British American, Imperial, Japan International and Philip Morris and their claim that the law would infringe on intellectual property rights. Some of the plaintiffs appealed the decision, which went before the appeals court this week. The three judges—Lord Justice Lewison, Lord Justice Beatson and Sir Stephen Richards—found that the health secretary was well within his rights to impose such a regulation. No word on whether the companies will appeal to the supreme court.

Also since May, tobacco companies have been prohibited from manufacturing cigarette packaging that doesn’t comply with the plain packaging rules, which state 65% of the front and back must have graphic health warnings. The companies have until May 2017 to sell off existing stock.

Meanwhile, in Australia, the illicit cigarette market has exploded in the four years since the country switched to plain packaging. Canada is also considering a plain packaging mandate, which retailers and tobacco firms are fighting. “Plain packaging simply doesn't work and will make it easier for criminals to sell cheap, illegal tobacco,” said Igor Dzaja, general manager of JTI-Macdonald Corp.