Special Report on South Korea: Military opponents preen and pose on Panmunjom border

"Please refrain from pointing, or making gestures or expressions which could be photographed and used as propaganda material against the United Nations Command," said our guide.

This did not stop the Australian air hostess next to me putting out her tongue at the only visible representative of the forces of communism, a North Korean soldier on the steps of a building opposite us.

Such childishness often seems appropriate at Panmunjom, the "truce village" which exists to maintain the armistice that ended the Korean War in 1953, and the only crossing-point between the two halves of the peninsula.

The North Koreans, after all, had raised a mound before constructing Panmungak, the building facing us, so that it would appear taller than Freedom House, where we were standing. It had also been made a metre wider.

Between the two buildings runs the military demarcation line, which is defined with the same pedantic exactitude as children might use in one of their games.

Within a hut which straddles the line, used for armistice meetings, the boundary is defined by a microphone wire running down the middle of the table. Visitors can walk round the table and be photographed in North Korea.

Every now and then, however, the game turns deadly. Two American officers in charge of a tree-trimming party were killed at Panmunjom in the 1970s when they were attacked by North Korean soldiers wielding axes. All along the 150-mile demilitarised zone (DMZ), the world's last Cold War frontier, where a million armed men are deployed on each side, there is a constant trickle of such incidents.

Late last year a US helicopter was shot down when it strayed across the line, killing one of the pilots, David Hilemon. The other, Bobby Hall, was returned after direct contacts between the US and North Korea, bypassing the armistice arrangements at Panmunjom.

This played into the hands of the Pyongyang regime, which likes to depict itself as the true representative of the Korean people and the Seoul government as a mere puppet of the Americans.

As the price of giving up its attempts to develop nuclear weapons, North Korea has insisted on wringing a measure of diplomatic recognition from Washington, which is about to exchange liaison offices with Pyongyang.

The North also resents the presence of South Korean troops at Panmunjom as part of the United Nations contingent, and has refused to attend any armistice meetings since 1991, when a South Korean general was appointed the senior representative on the UN side.

In 1953, when the UN commanders signed the armistice with their North Korean and Chinese counterparts, the Communist side nominated Poland and Czechoslovakia as "neutral" truce monitors, but today only China remains an ally. Peking was persuaded to withdraw from the armistice commission, and the Czech Republic's right to succeed to Czechoslovakia's role was successfully challenged, but the Poles clung on until last week, when their military observers were finally forced to leave Panmunjom under threat of having all supplies of food, water and electricity cut off.

Despite these occasional intrusions of new political realities, however, in most respects the "truce village" remains frozen in the past.

From a South Korean observation post near Panmunjom it is possible to see a locomotive in no man's land, slowly rusting where the tide of war caught it more than 40 years ago. At the westernmost extremity of the DMZ, there is the sad sight of a river with both banks lined by fences and guard towers.

Here people talk of the "Communist threat" and "the forces of freedom" with no sense of irony or anachronism.

South Koreans are also at pains to dispel the assumption that these divisions will melt as suddenly and peacefully as they did in Germany - pointing out, for example, that the West Germans outnumbered their eastern counterparts by three to one, while in the Korean peninsula the proportion of southerners to northerners is two to one.

Even West Germany, the third richest country on earth, had trouble absorbing the economic costs of reunification; in Korea there are fewer resources.

Above all, the two halves of Germany never went to war against one another.

North-South dialogue, suspended since 1990, is supposed to resume under the terms of last year's nuclear deal, but so far the regime in Pyongyang, where Kim Jong Il still appears to be consolidating his succession from his father, Kim Il Sung, has refused to take this seriously.

However empty the rituals at Panmunjom may occasionally appear, they have at least prevented prevented four decades of posturing turning into another war, and it is likely to be some time before they are no longer necessary.