In mid-Cold War, the US and Soviet intelligence agencies watched the May 1968 events in France with alarm. The French journalist Vincent Jauvert of the Nouvel Observateur went to archives in Texas and Moscow to search out the CIA and KGB reports of the time. The documents he found are startling.

Far from supporting Gen Charles de Gaulle's right-wing regime, the US blamed him for the anarchy in France and apparently hoped the Socialist patriarch, Pierre Mendes France, would take power. On May 30th, 1968, the head of the CIA, Richard Helms, sent a five-page secret memorandum to President Lyndon Johnson. De Gaulle had just returned from Germany, dissolved the National Assembly and vowed on television to save France from the threat of "totalitarian Communism".

Helms was merciless in his criticism of the general who had two years earlier expelled NATO headquarters from Paris. "The Gaullists have repeatedly violated and perverted their own constitution," he reported to President Johnson. "They have treated even the moderate opposition with disdain and indifference."

France was "on the knife-edge of disaster", Helms said. "By refusing to resign, de Gaulle has taken on the workers and students frontally. He has reverted to type, the powerful, challenging autocrat. . . He has come out of his corner swinging defiantly at opponents who thought that they had him on the ropes."

The general had divided France into those who were with him and his enemies - all considered Communist dupes. "When, how and if a head-on collision between right and left will occur is not yet clear, but a spark could set it off," the CIA chief reported.

To force de Gaulle to resign, 10 million striking workers might cut gas and electricity supplies and sabotage the factories they were occupying. If they did so, de Gaulle would have to call in the army - which Helms expected to obey orders. The CIA chief said de Gaulle could break the back of the rebellion if the labourers returned to work. "If not, civil conflict of major proportions will almost certainly ensue." In the short term, he thought the government could restore order and essential public services "but only at the cost of poisoning political life for the indefinite future . . . Whatever the short term outcome," Helms concluded, "France faces a period of unrest and, eventually, even civil war."

French officials believed the French Communist Party (PCF) and their Soviet backers were fomenting revolution. Nothing could have been further from the truth, as shown by secret telegrams sent in May 1968 by the Soviet ambassador to Paris, Valerian Zorine. In the words of the French historian, Jean Lacouture, Zorine had "the face of a starving alligator". The USSR's former ambassador to the UN Security Council, Zorine was also a member of the central committee of the Communist Party of the Soviet Union.

After a lengthy meeting at the embassy with the treasurer of the PCF, Gaston Plissonier, Zorine addressed the memo recently unearthed by Vincent Jauvert to only two people: the Foreign Minister, Andrei Gromyko and Boris Ponomarev, the head of the international department of the Soviet Communist Party.

Together, Plissionier and Zorine concluded that May 1968 must not be a new Bolshevik revolution. "The student movement has no serious prospects since the French students are mainly from the lower and middle bourgeoisie," Zorine wrote. "Those from the working class represent only 10 per cent, and what is more, the students are in the grip of leftist and Trotskyist elements."

The French government had failed to understand how much the Communists disliked their left-wing cousins. Ironically, Moscow wanted to keep the right-wing de Gaulle - the bug-bear of Washington - in power. Throughout the secret telegrams, ambassador Zorine railed against "leftists". A few days earlier, the student leader Daniel Cohn-Bendit had pushed his way in front of Communist demonstrators in a march, saying he was happy to be ahead of "the Stalinist toad".

The strategy of the PCF, related by Plissonier to Zorine, was "on the one hand to support the students against police repression and on the other hand to isolate the leftists who are trying to provoke further clashes with the police".

The PCF and its Soviet backers wanted to maintain control of the French working classes. Despite its revolutionary heritage, the PCF hoped to break out of its "internal exile" by consolidating ties with the Socialists and sharing power with them in government. The French Communists were deeply alarmed that de Gaulle named them as the enemy in his May 30th address. The last thing they wanted was to lose their "respectability" by provoking the intervention of the army, so Plissonier promised Zorine that gas and electricity workers would follow orders from the Communist trade union, the CGT, not to interrupt supplies. "In the absence of a revolutionary situation," Zorine concluded, "if the PCF had taken the path which the leftist elements wanted to drag them into, the Party would have doomed itself to destruction."