Eight young British servicemen who worked at a top-secret electronic listening post on Cyprus and were allegedly enticed into a sex-for-secrets ring set up by the Soviet espionage service are expected to go on trial here early this year.

According to sources here and in Washington, most of the servicemen were working at the facility at Akrotiri, on the southern coast of Cyprus, where Britain's Government Communications Headquarters operates an outpost that gathers electronic intelligence from the Middle East.

U.S. intelligence-gathering reconnaissance planes also are said to operate from there.

The Government Communications Headquarters, based at Cheltenham west of London, is the British equivalent of the top-secret U.S. National Security Agency at Fort Meade, Md.

Both U.S. and British sources said preliminary indications are that the ring does not appear to have caused a major compromise of western intelligence gathering and is not nearly as serious a breach of security as was the 1982 case of Geoffrey Prime.

Prime, now serving a 35-year jail sentence, was recruited by Moscow from within the intelligence agency's headquarters and is said to have provided extremely valuable information to the Kremlin over a period of years.

But there is special dismay and concern within U.S. intelligence circles because in the most recent case the Soviet KGB still was using the standard and seemingly ageless sexual entrapment schemes and because, despite the relatively obvious nature of such ploys, they continue to be effective at the operating level, especially among young soldiers and technicians.

A number of sources said the ring involved homosexual entrapments, but one source said it could involve heterosexual enticements as well.

The servicemen were rounded up last summer in a British security sweep through installations at Akrotiri and Episcopi, another nearby outpost.

Under Britain's Official Secrets Act, the arrests have been kept relatively quiet and were overshadowed by what appeared to be a much more sensational case last summer. That involved Paul Davies, another 21-year-old Royal Air Force technician based at Episcopi, and a glamorous, 31-year-old, Hungarian-born woman who also was alleged to be a spy.

The British press quickly dubbed the woman "Mata Hari" for the legendary World War I spy, and the story was big news here for weeks this summer. The young airman, however, ultimately was cleared of charges that he passed NATO secrets to the woman in return for her promise of sexual favors, and sources said this case did no damage.

Sources said they believe there is no espionage connection between the Davies case and the arrest of the eight other airmen. However, it was at the time security authorities began looking into the first hints that Davies might be a problem that the much bigger alleged homosexual sex-for-secrets ring was uncovered.

Although some British newspapers included a brief mention of this bigger, and potentially much more important, security sweep in the coverage of the Davies trial, the classic allure of the beautiful, mature woman and the disco-dancing young airman with the top-secret job dominated the headlines.

At the time of the Davies trial it was observed by the airman's defense counsel that, in his view, the government had contributed to the show trial nature of the hearing in an effort to show Britain's allies that it was cracking down hard on suspected spies. It also was alleged that the trial had been orchestrated on false evidence to deter other servicemen from letting their guard down.

During his trial, Davies said he had been bullied into making confessions by Air Force investigators.