Tales of espionage, latter-day and past, featuring accused spies alive and long dead, sinister and merely sad, poured forth across London today.

In the most serious case, Hugh Hambleton, 60, a British subject who most recently taught economics in Canada, pleaded not guilty to spying for the Soviet Union since 1956, including a period up to 1961 when he worked for NATO.

Despite the plea, Attorney General Michael Havers, said Hambleton told British police he had given the Soviets considerable classified material over the years concerning "economics, politics and oil."

"This defendant," Havers said, "is and was a spy."

The attorney general said Hambleton had claimed to police that he met with the new Soviet Communist Party leader Yuri Andropov, then head of the KGB, at a Moscow apartment in 1975. He said Andropov appeared to want an assessment of world trouble spots and suggested the professor run for political office in Canada, using money supplied by the Soviets.

"His English was very good," Hambleton allegedly said of Andropov, "and he had a good grasp of the West."

The other cases today were of lesser magnitude. Rhona Ritchie, 30, a British diplomat formerly stationed in Tel Aviv, admitted giving confidential information to her lover, an Egyptian diplomat, and was given a nine-month suspended sentence. The information concerned the setting-up of the multinational force to police the Sinai when Israel returned it to Egypt last spring.

Ritchie, the attorney general said, was "more foolish than wicked." She was dropped from the Foreign Service.

A lance corporal serving in Army intelligence was the final suspect in today's news. He is under arrest for allegedly contacting the Soviet embassy in London during the Falklands war. As yet, however, there is no indication that he actually passed information and the investigation is continuing.

Ordinarily, with the exception of the Hambleton case, the others might have passed unheralded. But the recent case of Geoffrey Arthur Prime, the Soviet spy who worked for years in Britain's Cheltenham center for electronic intelligence, has given the country a fit of security jitters. The merest suggestion of any further breaches brings renewed calls for a government crackdown.

Parallel to today's installment, right-wing members of Parliament in Prime Minister Margaret Thatcher's Conservative Party demanded a full judicial inquiry into the "parlous" state of national security. They reacted to the apparent suicides of two Cheltenham employes over the past few months, news of which appeared on top of all the other cases.

Speaking primarily of Prime, Member of Parliament David Storey asked, "How many more such cases have to unfold before somebody wakes up to the appalling danger in which the nation stands?"

There is no indication that either suicide at Cheltenham was security related. But the legislators argue that any chance that the people involved were working with Prime after he left the agency in 1977 had to be exhaustively examined. Thatcher has maintained that security procedures are being reviewed, but the calls for more action go on.

Among devotees of British intelligence stories, an echo out of the past this weekend stirred interest. A new book discloses that the British intelligence agency MI5 employed the late Stephen Ward, long portrayed as a "society osteopath" in the celebrated sex and security scandal of the early 1960s that forced the resignation of war minister John Profumo.

Ward, who committed suicide in 1963, was apparently recruited by MI5 in an effort to trap a Soviet diplomat who was involved with the same call girl, Christine Keeler, as was Profumo. At the time Ward insisted he had an intelligence connection, but no one believed him.

"If the security services had spoken up for him," one former official was quoted as saying in the London Sunday Times, "he might never have been driven to his death."