The leader of Europe's most corrupt country has pleaded for it not to be judged by the same high standards as established EU states, after being told to speed up reforms or lose funding.

Sergei Stanishev, the Bulgarian Prime Minister, told The Times that it was unfair to expect his country to have reached the same levels as Sweden after only two years as a member of the European Union.

With critics suggesting that Bulgaria was allowed to join the EU too hastily to avoid its turning back towards Russia, José Manuel Barroso, the European Commission President, said that he would not tolerate any second-class states. He called for evidence in the next few months that reforms to the judicial and police systems in Sofia were delivering results.

Mr Stanishev has struggled to persuade Brussels to release more than €500 million (£470 million) of aid that has been frozen because it might be at risk from corruption. In Bulgaria there is a growing chorus, including in Mr Stanishev's party, to look more for financial support from Russia, which is offering lucrative energy deals through Gazprom.

Mr Stanishev, 42, who was educated at the London School of Economics and is chairman of the Bulgarian Socialist Party, argues that Brussels has not taken fair account of the progress made to tackle corruption. "I have always asked the international experts to assess and compare Bulgaria to Bulgaria; not Bulgaria to the Netherlands and Sweden with their historical traditions, democracy and market economy, but Bulgaria five years ago to Bulgaria today. Its progress is impressive," Mr Stanishev told The Times.

"The ambition of the Government is to accelerate reforms. There is such a tight schedule of reforms - legislative changes, organisational measures, personnel changes and everything else - which not many governments would be able to follow in Europe," Bulgaria has forfeited €220 million in aid because the EU lost confidence in the agencies created to allocate funds. The decision was taken in part because the director of the highways agency handed a contract worth €50 million to his brother. Several Bulgarian farmers were caught trying to claim EU agricultural funds for graveyards and sports stadiums.

Mr Stanishev has replaced key figures in the Interior Ministry and created an independent police force to try to break internal corruption, but there have been few prosecutions for high-level corruption and not one mafia conviction despite 150 gangland murders.

Mr Stanishev argued that rules were being bent in Brussels for countries to enable them to stay in the single currency. His implication is that Bulgaria should be given more time to solve corruption, even if it means relaxing strict financial safeguards.

The response from Mr Barroso has been implacable. "We need concrete and convincing results in judicial reform, the fight against high-level corruption and the fight against organised crime," he said. "Bulgaria is treated like every other member state. There are no second-class members."

Ivailo Kalfin, the Bulgarian Foreign Minister, attacked Brussels and praised Moscow this week. "We think that the way which the European Commission maintains dialogue with Bulgaria is unacceptable for an EU member state," he told the Bulgarian newspaper Standart.

He added that Sergei Lavrov, the Russian Foreign Minister, had told him that joint energy projects with Bulgaria were his top priority.

Cost of cheating

- The EU has earmarked €11 billion towards Bulgarian infrastructure over the next six years

- In July the European Commission suspended €121 million of farming aid, €144 million of road subsidies and €560 million for regional development

- Bulgaria is ranked 72nd in this year's corruption perception index compiled by Transparency International. Sweden is joint top

- In a survey, 76 per cent of Bulgarians agreed that criticism by the European Commission over corruption was warranted