Only weeks after the cabinet was formed, senior posts in the new government are being bought for money and some of Russia's most powerful ministers are linked to "circles which are extremely corrupt", Mr Yavlinsky said in an interview. His allegations will carry considerable weight because Mr Yavlinsky is a vocal supporter of Yevgeny Primakov, prime minister since Sept 11, who, he stresses, is not involved in the abuses. 

Mr Yavlinsky was the first politician to call publicly for his appointment and, with President Yeltsin's health in rapid decline, he is highly supportive of Mr Primakov's new role as vice-president in all but name. Mr Yavlinsky, leader of the liberal, Yabloko party, said: "We support Mr Primakov because he is a solution to Russia's political crisis. But we are not going to keep silent about what is going on inside the cabinet. Corruption can determine who gets what position. My people inside the government tell me you can buy offices for money." 

Although he refused to name culprits, he identified the problem as being particularly acute among members of the new government whose sympathies belong to Russia's Left. Allegations of corruption in public life are nothing new in Russia, but by surfacing so soon after the government was formed, they will cause a political scandal. 

Mr Yavlinsky's accusations will embarrass Mr Primakov, a former head of Russia's foreign intelligence service, who even boasted on taking office that he would use his intelligence contacts to vet would-be ministers. They will also provoke increased unease in the West about Mr Primakov's government, which is pressing the International Monetary Fund (IMF) for a £2.5 billion loan but has yet to approve its own plans to deal with Russia's economic crisis. 

Mr Yavlinsky, 46, is respected in the West, and - uniquely among Russia's reformers - he also enjoys considerable support in his own country as well. His allegations of corruption in high places thrust him back into the limelight of Russian politics after he underwent treatment for heart problems in Germany. Himself a candidate to be the next president, he has returned to a country where election campaigning is already in full swing.