Britain's estblishment has closed ranks to bring a rapid end to the affair of Anthony Blunt, whose confession to being a Soviet spy was kept secret for 15 years while he remained a knighted art adviser to the queen.

There are to be no investigations by groups equivalent to congressional committees or presidential commissions into Blunt's case or the clear indications that other, still unnamed prominent figures in postwar Britain were agents of foreign powers.

In Parliament, opposition leader and former prime minister James Callaghan joined with the present prime minister, Margaret Thatcher, in deciding that "There should not be a further inquiry into the Blunt conspiracy."

In Callaghan's view, it could only mean that "innocent names would be bandied about as they had been so far." Another former prime minister, Edward Heath, warned against the danger of "McCarthyism," referring to the hunt for communists conducted in the U.S. in 1950s by Sen. Joseph McCarthy.

Government officials told reporters that the reputation of Britain's reorganized intelligence services would unnecessarily be placed at risk by dredging up more scandal from a nearly forgotten past. Blunt's own account of the affair in televised interviews last week, Callaghan said, "was like the rustle of dead leaves."

Any further inquiries will now have to be conducted by journalists. One author and former BBC newsman Andrew Boyle, forced the unmasking of Blunt in the first place. But the British establishment, which once was so easy for the KGB to penetrate, is much more effective at keeping secrets from the British press and public.

The Blunt affair forced Thatcher to kill legislation that would have further strengthened legal protection of official secrets here. The British government, however, still has sweeping and intimidating powers to stop its employes from giving unauthorized information and journalists from receiving and publishing it.

In addition, broad contempt powers enable judges to control tightly what is published about the courts and cases in progress. Strict libel laws also enable anyone with the money to hire a good lawyer to silence most press criticism of or investigation into their affairs.

Because of Britain's strict laws, Boyle gathered much of his information about British intelligence services from U.S. documents. He and an American author used the Freedom of Information Act to obtain about 3,000 pages of CIA, FBI and State Department files.

Some British officials, scholars and journalists are critical of the secrecy provisions here.

"What the present government cannot grasp," said Christopher Andrew, a Cambridge University historian and expert on Britain's security services, "is that official secrecy on so exaggerated a scale . . . far from protecting national security, actually serves to undermine it. For its very extravagance it threatens to bring the whole concept of secrecy into disrepute."

Thatcher's government had introduced liberalizing amendments to the Official Secrets Act in Parliament, but withdrew them under pressure last week. Critics in the media and among academics discovered, however, that fine print to the amendments actually would have given individual government officials more power than ever to restrict the release of information and punish leaders.

In a country where it is already not pssible to publish the names of the men who head the two intelligence-gathering agencies for example, it would have specifically become a crime to disseminate or publish any information about government wiretapping, even the fact that it existed at all or the laws and rules governing it.

One government official, asked by his superiors some time ago to give his assessment of the legislation, demurred.

"How could I speak well of secrecy legislation that would be restrictive and undemocratic as South Africa's?" he later asked rhetorically.

Thatcher has asked her civil servants to draft new legislation, but government officials say nothing should be expected soon. They clearly want the current argument about government secrecy, like the Blunt affair, to blow over first.