LONDON (AP) _ The High Court ruled Thursday that it was not a criminal offense to flash a subliminal image on TV screens so fast that it couldn't be seen but would still register in the mind.

Norris McWhirter, co-founder of the Guinness Book of Records, claimed the weekly satirical show ''Spitting Image'' had repeatedly shown ''a grotesque and ridiculing image'' of his face superimposed on the top of a naked woman's body.

McWhirter, 60, said he asked for the summons after his 14-year-old nephew discovered the fleeting image of his uncle's head on the nude torso by using the ''freeze frame'' button on his video recorder.

McWhirter argued that broadcasting such a subliminal image was a criminal offense under the 1981 Broadcasting Act, which regulates commercial television in Britain.

The act requires the Independent Broadcasting Authority to make sure subliminal images are not telecast, the court said. But, it ruled, it is not a crime if the authority fails its duty.

McWhirter claimed the image, flashed for less than a quarter of a second, exploited the possibility of conveying a message to influence the minds of the public without their being aware of what had been done. He said that was a breech of the Broadcasting Act.

But the judges, Sir Anthony Lloyd and Sir Henry Skinner, quashed McWhirter's summons against the broadcasting authority and canceled further proceedings in the case.

McWhirter said he would petition the House of Lords for the right to appeal.

James Conway, a spokesman for the Independent Broadcasting Authority, said when it established that ''Spitting Image'' was broadcasting a subliminal image, the authority contacted Central TV, which produces the show, and ordered them to stop.

''They shouldn't have been doing it and we reminded all companies in the Independent Television system of their obligation under the Broadcasting Act not to use such messages. Central TV admitted it was an error on their part,'' he said.

Handing out photographs of the offending frame after losing the case, McWhirter said: ''The reason I took criminal rather than civil proceedings was because transmission of subliminal messages has been repeated. It has also been admitted in writing.

''Transmission of subliminal images is essentially deceitful. I want them stopped,'' he said.

Conway said there was one previous instance in the 1970s when a subliminal message was used in a Labor Party political broadcast on Independent Television. It was challenged in the courts by McWhirter's brother, but thrown out because the judges ruled that the broadcasting authority had no control over political broadcasts, he said.