Flower delivery network Interflora has won its long-running trademark dispute with Marks & Spencer.
The case concerned the use by M&S of the word "Interflora" as an advertising keyword leading Google internet search engine users to advertisements for M&S flower delivery services.
Interflora's claim against the retailer, which began in 2008, reached the European Court of Justice before being redirected to the High Court for a decision.
Mr Justice Arnold, in London, ruled that M&S's use of the "Interflora" trademark as a Google Adword to advertise its M&S Flowers and Gifts website was trademark infringement.
He said that the M&S adverts complained of did not enable "reasonably well-informed and reasonably attentive" internet users - or enabled them only with difficulty - to ascertain whether the service referred to originated from M&S or Interflora.
On the contrary, as of May 2008, a significant proportion of the consumers who searched for "Interflora" and then clicked on M&S's adverts displayed in response to those searches, were led to believe, incorrectly, that M&S's flower delivery service was part of the Interflora network.
Rhys Hughes, president of Interflora British Unit, said later: "This ruling helps ensure that when consumers search on the internet for "Interflora", they can be confident in knowing that the flowers bought online come from a member of the Interflora network.
"Keyword advertising is a very powerful tool and so it is vital for consumer protection that internet search results take consumers directly to the brands they are looking for.
"The Interflora brand stands for quality and service, a reputation we have been building, with our network of independent florists, since 1923."
The case is expected to return to court later in the year to decide the issues of damages and costs.