LONDON – Britain is tightening the noose around counterfeiters in cyberspace — and demanding that Internet service providers play their part.

Britain’s Court of Appeal has upheld a 2014 decision forcing the country’s Internet service providers to block web sites selling counterfeit goods.

Several big providers, including BT, EE and Virgin Media, lost their appeal earlier this summer to overturn the High Court’s 2014 ruling.

The ruling was the first of its kind by a senior court regarding counterfeit blocking in Europe. Advocates say it is a clear win for brand owners and designers who are increasingly battling online counterfeiting.

The original ruling was a particular triumph for Compagnie Financière Richemont, which had originally brought the case to court. The High Court ruled that five major providers block access to the rogue web sites, which were selling fake Cartier, Montblanc and IWC Schaffhausen products.

The landmark ruling created a framework for Richemont and other luxury groups and designers to apply for court orders to block access to the sites, rather than having to take action against the web sites themselves — an arduous task since there can be hundreds of them, meaning a company must tackle each one.

Paula Levitan, a partner at the international law firm Bryan Cave LLP, said that the Court of Appeal’s decision was significant because it crystallizes the responsibilities of the Internet service providers.

She pointed out that while the providers do not have a monitoring duty, they must act if they are made aware of the counterfeit sites. “When they are made aware of a counterfeit site, they have an obligation to block it, and they can be injuncted if they do not,” she said in an interview with WWD.

Levitan said the Internet service providers had argued that rogue sites were not their responsibility. “The ruling has made clear that if the ISPs are made aware, they do have to take down these sites,” she said.

“They don’t have an obligation to monitor — that is the burden of the brand owners,” said Levitan, adding that intellectual property is important to companies large and small, and that more and more designers and brands are aware of their rights today and more active in seeking legal recourse to protect them.

The original court action in 2014 came in response to a growing number of sophisticated sites selling fake goods — often with U.K. addresses — that had regularly duped customers into believing they were legitimate.

In lieu of legal action, Richemont had in the past worked in partnership with other firms such as eBay to remove fake goods for sale online.

Frederick Mostert, who retired as chief counsel at Richemont shortly after the original decision was handed down, spearheaded the original case.

He was formerly president of the International Trademark Association. Last year, Mostert was inducted into the Intellectual Property Hall of Fame.