The case brought the smartphone industry’s bitter international patent wars to British shores and is likely to have an impact on ongoing disputes in Germany and the United States.
Along with the slide-to-unlock mechanism, HTC challenged Apple’s patents on the iPhone’s groundbreaking multi-touch system. Both are “prize” patents in the American giant’s portfolio, according to intellectual property experts.
The other patents in the case related to the way the iPhone manages photographs, and the use of different character sets in text messaging; a patent dating back to 1994.
A HTC spokesman welcomed the High Court’s ruling, which said that parts of the slide-to-unlock patented were too “obvious” or foreshadowed by earlier patents. The multi-touch patent was also found to be partly invalid because it was too obvious, and Mr Justice Floyd said HTC’s smartphones did not infringe what remained.
Only the Apple’s photo management patent was found to be entirely valid, but Mr Justice Floyd said HTC had not infringed it.
“Today, the English High Court found that three of four patents claimed by Apple to be infringed by HTC were invalid, and that HTC did not infringe the fourth,” said an HTC spokesman.
“One of the invalidated patents is Apple’s flagship ‘slide to unlock’ patent. Apple’s photo management patent was found not to be infringed.
"HTC is pleased with the ruling, which provides further confirmation that Apple’s claims against HTC are without merit.
“We remain disappointed that Apple continues to favour competition in the courtroom over competition in the marketplace.”
Apple declined to comment on the case but a spokesman said: "We think competition is healthy, but competitors should create their own original technology, not steal ours."
Peter Bell, an intellectual property specialist at the law firm Stevens & Bolton, said the case was likely to have “significant ramifications” across Europe.
“As well as suing HTC in the UK, Apple has also asserted all of these patents against Samsung in the UK and it has asserted the foreign equivalents of some of these patents against HTC, Samsung and Motorola in Germany and the Netherlands,” he said.
“Apple has even succeeded in getting injunctions against some of Samsung and Motorola’s products in the Netherlands and Germany on the basis of some of these patents."
For instance, in February, Apple obtained an injuction in Germany barring sales of some Motorola devices over their alleged infringement of the slide-to-unlock patent.
“A highly respected venue for patent litigation, [the High Court’s] findings could well influence the German and Dutch courts,” suggested Mr Bell.
Tim Cook, Apple’s chief executive, has described the smartphone patent wars as a “pain in the a--“, but there seems little prospect of a truce. Under Steve Jobs, who believed Android was a shameless rip-off of iOS, the firm launched a salvo of lawsuits against Google’s manufacturing partners around the world that prompted many counter-suits.
“Given the current thirst for patent litigation in the smartphone market, Apple seems more likely to react [to today’s defeat] by launching a counter-offensive than by backing down,” said Mr Bell.
Observers argue that the legal onslaught is stifling innovation in the smartphone market, with corporate energy focused on courtroom attack and defence instead of product development.