Michael Straight, a Washington-area writer, a former editor of the New Republic and former deputy chairman of the National Endowment for the Arts, said yesterday he was the man who exposed eminent British art historian Anthony Blunt as a Soviet spy.

His revelation comes amid a series of charges published this week implicating leading British intelligence figures during World War II in yet another spy scandal.

Straight said Blunt -- the queen's longtime personal art curator who was stripped of his knighthood after Prime Minister Margaret Thatcher revealed his past as a spy in a statement to Parliament in November 1979 -- tried to recruit him as an agent at Cambridge University in 1937.

Straight said he revealed his knowledge about Blunt to then-attorney general Robert Kennedy in 1963 after he learned that the president planned to name him to the newly formed Endowment for the Arts.

"I had ruled myself out for the job" because of what was likely to be learned from government security checks, Straight said in a telephone interview last night, although he emphasized that he flatly rejected Blunt's attempt to recruit him.

The FBI, Straight said, gave details of the recruitment attempt to British security officials, who ultimately successfully confronted Blunt with his treason. Blunt, in exchange for immunity from prosecution, secretly confessed his role as a talent-spotter for the Soviets at Cambridge, his passing of secrets to the Soviets while working for British intelligence during World War II, and his help in the escape from Britian to Moscow of fellow spies Guy Burgess and Donald Maclean.

Allegations in Britain's current spy scandal have made headlines in London all week, as the Daily Mail has been serializing a book by its defense specialist, Chapman Pincher. The latest allegation, published today in London, is that Britain's third-ranked spy at the end of World War II, Charles Howard Ellis, cooperated with Nazi Germany and the Soviet Union for 30 years.

Pincher's report Monday that there were strong suspicions that the late Sir Roger Hollis, former chief of Britain's M15 counterintelligence service, was a Soviet spy, prompted demands in Parliament for a government inquiry and a scheduled appearance in the House of Commons today by Thatcher to reply to the allegations. The prime minister reportedly summoned top security officials yesterday to discuss the charges.

According to news service reports of the Daily Mail articles, Pincher charged that Ellis made an "abject confession" in 1965 of spying for Germany up to 1940, and admitted to handling over detailed charts of British intelligence, knowing they would go both to Germany and the Soviet Union.

According to The Associated Press, the Daily Mail said Ellis did not admit to spying for Germany after 1940 or for the Soviets following the war, but said his interrogators believed he acted as an agent for the Nazis before and during the war and later for the Soviet Union.

Ellis, a former Oxford University student born in Australia, allegedly was recruited for the Nazis by a relative and later decided to work for the Soviets purely for the money, the newspaper said.

Straight said he met Blunt in a group of student intellectuals at Cambridge who opposed the growing international fascist movement. He said the group was typical of many student action groups at the time in that they tended to be led by the extreme left.

"These organizations were not formally called communist organizations," he said, but there were in them "outsiders like myself who were drawn into the circle because of a desire to do something about Germany, about Japan and about Italy."

Straight said that the Soviet Union apparently had decided to use these leftist-led groups as a recruiting ground for agents, usually without the knowledge of the leftists themselves. He said he was approached by Blunt after his best friend, an active Communist named John Cornford, died fighting in the Spanish Civil War on his 21st birthday.

"They said they had decided to accelerate their timetable" in a plan to recruit him as an agent, "because of the death of my closest friend," Straight said. He said he was "stunned and shocked" and said no.

Straight said the agents' plan was to have him return after his studies to the United States and work for the J.P. Morgan company, writing economic appraisals. His father, the well-known diplomat Willard Straight, was connected with the Morgan firm.

Straight said he did not consider Blunt a threat during the war, since the Soviets were allies and he regarded the art historian as a "humane scholar."

He said he felt that Burgess, who was also a member of the Cambridge circle, had brought Blunt into the spy scheme. Blunt had been questioned by British intelligence since Burgess and Maclean defected to Moscow in 1951, Straight said, but there was no hard evidence against him until new information was received in 1964. Straight, who had decided in late 1963 to go to the FBI with his information because of his prospective appointment to the Endowment, was flown to Britian in 1964 and taken to Blunt's apartment.

Blunt's public exposure in 1979 came after publication of a book by Andrew Boyle hinting at his identity as the "Fourth Man" in the spy ring of Burgess, Maclean and Kim Philby.

In an interview with Angus McPherson of the Daily Mail, which published the first account of Straight's story, he said Blunt was "genuinely relieved" at having been found out, because the art scholar never could have admitted his own actions.