Alexander Dubcek's election as general secretary of the Communist party was not headline news in Britain in January, 1968. Yet because I had been a student in Prague a year earlier, I was more aware than most of what it meant. His predecessor, Antonin Novotny was a loathed creature. While life in both Poland and Hungary had started to ease up, Czechoslovakia remained a Stalinist bulwark on the USSR's western flank. Censorship was a fact of life. As was self-censorship.
Over the nine months I had lived there I had got used to sudden silences and warning glances.
By April, when I was offered a job interpreting on an American film being made on location a few miles down river, the Prague Spring - which took its name from the annual classical music festival - was well under way. Censorship, under Dubcek's leadership, had been effectively abolished. Novotny, who had clung on as president, was out in the cold, replaced by the father-Christmas look-alike, Josef Svoboda, whose very name - it means "freedom" in Czech - seemed an augury for the future.
I arrived in early May. The change since 1966 was extraordinary. People would stand about chatting on street corners. Cafes were thronged and buzzing. Dubcek's smiling face appeared in every edition of every newspaper. Fly posters covered every available surface: meetings here, rallies there: beckoning workers and students. No one was excluded. But, like children let loose in a sweet factory after years of starvation, they had no idea how to pace themselves. "Socialism with a human face" (Dubcek's anthem) soon gave way to more dangerous words such as freedom, democracy and neutrality. As if to say: "If it's OK to go this far, then why not the whole hog?"
Working in the press office of the film, part of my job was to keep track of whatever journalists were around. But the reporters sitting around the Alcron hotel that summer had no interest in the antics of movie stars. They were the elite of the world's foreign correspondents. Prague was a tinder box waiting to blow and they would stay until it did. Rumours abounded. Some were genuine, others were more Machiavellian in intent. A rumour only had to be repeated three times and it became fact. Most journalists had interpreters, but for the canny among them an English girl who spoke Czech was useful.
By late June I was already worried. With the abolition of censorship, foreign newspapers were now openly on sale and so I could read what the world was being told was happening. The pressure on these highly-paid journalists to file something - anything - every day was enormous. Rumours and half-truths were regularly being printed, regularly misrepresenting the situation. Whether the result of laziness or manipulation, I will never know. But I am as convinced now as then that these reports provided the ammunition the Politburo needed for an invasion. The old war horses sitting in Moscow, what did they care for the truth? If it was good enough for the London Times/Telegraph/New York Times, it was good enough for them.
In early June, troops belonging to the Warsaw Pact had crossed the borders from Poland and Germany. "Essential manoeuvres." They didn't make their presence felt. They just didn't go. In July, Breznev and Dubcek had a summit at a village on the Slovak/Russian border called Ciernounad Tisou. Knowing this was a moment of history, I hitched a lift with a BBC crew. Everyone held their breath. Then the Russians went away, and all seemed well - until the early hours of August 21st when the skies above Prague were filled with planes and the city shook as the might of the Warsaw Pact rumbled through the streets.
Seven long days later it was all over and the borders - open for a bare six months - were once again closed. "Do not forget us when we are no longer news", implored a slogan. But we did. The foreign correspondents slipped their traces and left on some other assignment or returned to Vietnam: that story still had another six years to run.
The Czech Republic is now a fledging democracy funded by multinationals and tourism. The boys and girls who put roses in the gun barrels of Russian tanks are in their 50s and 60s and quite out of kilter with the new consumerism. Some went into parliament after the Velvet revolution in 1989. But few remain. For them, as for their whole generation, it was a summer that came too late.