In Monday's High Court judgment Judge Colin Birss said that Samsung's Galaxy tablets belonged to the same family as the Apple design when viewed from the front, but the Samsung products were "very thin, almost insubstantial members of that family with unusual details on the back".
"They do not have the same understated and extreme simplicity which is possessed by the Apple design. They are not as cool," he said. "The overall impression produced is different."
The victory for Samsung comes days after a U.S. appeals court lifted a freeze on sales of its Galaxy Nexus smartphones, although it upheld a lower court's decision to temporarily halt sales of its Galaxy 10.1 tablet.
The two companies are waging legal battles in about 10 countries, accusing each other of patent infringement as they vie for supremacy in the mobile device market.
Samsung welcomed the British High Court judgement, which it said affirmed its own intellectual property rights while respecting those of other companies.
"Should Apple continue to make excessive legal claims in other countries based on such generic designs, innovation in the industry could be harmed and consumer choice unduly limited," Samsung said in a statement.
Apple said it had no comment on Monday's judgement, but it reiterated its view on the South Korean company's designs.
"It's no coincidence that Samsung's latest products look a lot like the iPhone and iPad, from the shape of the hardware to the user interface and even the packaging," the company said.
"This kind of blatant copying is wrong and, as we've said many times before, we need to protect Apple's intellectual properties when companies steal our ideas."
(Reporting by Paul Sandle; Editing by Sophie Walker)