South Korean politics are on the brink of meltdown after spiralling public hysteria over “mad cow” disease in American beef unleashed a weekend of mass protests and pitched battles between demonstrators and riot police.

Police vehicles were today attacked by angry mobs armed with sticks and police lines were reportedly charged after the 40,000-strong crowd of peaceful protesters thinned-out to leave a smaller group of activists.

With the violence threatening to continue for another week, and the calls for his resignation being screamed by students on the streets of Seoul, President Lee Myung Bak now faces a series of potentially crippling departures from his immediate circle of allies.

Just a few short months since taking the reins of power in South Korea with pledges of stronger government, Mr Lee is expected within the next couple of days to receive letters of resignation from his Prime Minister, Han Seung Soo, half a dozen members of his cabinet and a number of his closest aides.

Government sources said that a “collective resignation” was a near certainty over the next few days because of the persistent failure of Mr Lee’s government to calm a population that believes its leaders are playing fast and loose with an issue of public health.

The weekend’s violence was the culmination of rising fury over a government plan to resume imports of American beef after a five-year suspension.

The discovery of a case of BSE in a cow in the US in 2003 prompted several countries to suspend imports. Washington has slowly managed to persuade large former customers like Japan to resume their imports, but it was only in April that Seoul agreed to do so.

But many South Koreans – via some of the most active internet message boards in the world – objected strongly to that decision, arguing that this was an example of Mr Lee being too acquiescent towards the US.

Sensationalist television documentaries involving questionable science and supposed footage of cows staggering around farmyards, further roused public suspicion in the face of repeated assertions by the US Department of Agriculture that American beef was entirely safe.

Schoolchildren and university students have been especially vocal in their distrust of Mr Lee and his government, and could be seen waving placards bearing phrases like “Why must I die like a mad cow?”

With his control over public opinion now in tatters, and his plan to resume US beef imports in limbo, Mr Lee received a phone call from George W Bush on Saturday in which the US President promised that only US beef from younger cattle would be sold to South Korea. It was not enough to calm the mood on the streets, however.

The scenes in the capital over the weekend, which were repeated on a smaller scale in towns across the country, deal a heavy blow to a president who has all but lost the support of the country. Young Koreans who were initially whipped into a frenzy over the issue of US beef imports on hundreds of internet message boards have become increasingly vocal and physical in the streets.

The rioting follows six weeks of demonstrations that have sent the approval ratings of Korea’s new president plunging below 20 per cent. Mr Lee was voted in by a huge landslide last December, but has had barely a moment to flex his political muscles. Even by the fickle standards of South Korean politics, say analysts, his fall from grace has been surprisingly hard and fast.

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