North Korea's probable test of a nuclear weapon on Monday has triggered the second nuclear crisis in 13 years on the Korean peninsula.

In 1993, North Korea announced it would pull out of the Nuclear Non-Proliferation Treaty, leaving it free to divert nuclear material from its energy reactors to make a nuclear weapon and setting off a round of crisis diplomacy led by the Clinton administration. The result was the so-called agreed framework, which – in return for supplies of fuel oil to North Korea – froze most aspects of Pyongyang's nuclear weapons programme for the rest of the decade.

The agreed framework was in effect consigned to history when the Bush administration came to power in 2001. The new administration argued that although the road to a plutonium-based nuclear bomb had been frozen, the North Koreans were cheating by attempting to develop a uranium-based bomb that was not explicitly addressed by the agreement.

That five years later, North Korea has tested a nuclear weapon will be widely interpreted as a sign of the failure of the tougher approach favoured by the Bush team.

The test followed an earlier provocative test of seven ballistic missiles in July, which came in spite of worldwide warnings, including from its main ally and neighbour China. The only missile of the seven potentially capable of reaching the US fizzled however, blowing up seconds after launch.

That – and the difficulties of miniaturising a nuclear warhead even if Monday's test proves to have been successful – means that North Korea appears to be some years away from successfully "weaponising" its bomb. However, there are potentially other, cruder, means of delivering a weapon – such as in a ship – that could worry its neighbours and antagonists, though the likelihood that Kim Jong-Il would sign his own death warrant by delivering such a weapon is low.

The test does imply, however, that the regime has enough weapons spare not to worry about losing one of them by testing. This probably means that it has more than the one or two weapons it was assessed to have by US intelligence a few years ago, and may have as many as 10.

Yet the test is more a sign of weakness than of strength. Though analysing what goes on at the top of the isolationist regime is difficult, some analysts have speculated that Kim Jong Il is under internal pressure. The country is plagued by food shortages – exacerbated by a drop in food aid from China and other countries – and has seen economic sanctions erode its ability to earn foreign exchange. The US-inspired seizure of accounts last year at a bank in Macao used by the regime appears particularly to have angered Pyongyang.

North Korea is also sandwiched by two economic powerhouses: South Korea and China. Though according to the International Institute of Strategic Studies, the north has 1.1m under arms, its conventional military is poorly equipped and maintained.

North Korea has a population less than half the south's 49m, while its economy is an estimated 40 times smaller than that of the south. That would mean that the south's defence budget – put by the IISS at $23.5bn this year – is equal to the size of the North Korean economy.

Copyright The Financial Times Limited 2006

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