FIFTEEN years after Yugoslavia descended into a succession of civil wars that claimed more than 100,000 lives, the last of its constituent states is about to slip away.

The final phase in the disintegration of a former regional power has been set in motion after the political leaders of Montenegro, a tiny Balkan province of 650,000 people, gave the go-ahead to a referendum on becoming independent from Serbia.

The province’s parliament was due to agree the May referendum last night just as a United Nations mediator arrived in neighbouring Kosovo for talks that may well lead to its independence.

Montenegro, which is the size of Northern Ireland, is the only one of the six constituent parts of the erstwhile Federal Republic of Yugoslavia not to have achieved independence after the communist state collapsed in 1991. If it votes to become autonomous it will be Europe’s first new country since 1993 when Slovakia and the Czech republic divorced. It will automatically be on course to join the European Union, where it would be the smallest member after Luxembourg and Malta.

The mountainous and thickly forested province – whose name means “black mountain” – had been an independent country for almost a thousand years until it was forcibly absorbed into Yugoslavia at the end of the first world war. Montenegrins are proud that they are the only part of the Balkans not to have succumbed to Turkish rule during the Ottoman empire.

The parliament voted on the referendum after it was approved in principle by EU foreign ministers on Monday, who agreed the poll could go ahead on condition that independence would be declared only if the proposal was supported by a voting margin of more than 55 per cent to 45 per cent.

Although the pro-independence prime minister Milo Djukanovic said the threshold was undemocratic, he told Miroslav Lajcak, the EU envoy to Montenegro, he would accept it.

“I don't believe that the Montenegro government would choose to step into contradiction with the EU over this issue," said Mr Lajcak. The EU keeps Balkan countries in line with aid, expertise, security and — most persuasively — the prospect of EU membership.

Brussels had long sought to thwart Montenegro’s growing separatist movement, fearing that any move would destabilise the already turbulent region. Serbia has vigorously resisted Montenegro’s independence, not least because it would lose its access to the Adriatic coastline and become a landlocked country.

Montenegro already has a considerable degree of autonomy from Serbia, which is more than ten times its size. It has a separate parliament, government and currency – it uses the euro.

The joint policies are defence, foreign affairs, internal trade, EU integration and human rights. Both have Serbian as the official language and both are predominantly Orthodox Christians. Montenegro – which, unlike Serbia, was largely bypassed by the Balkan wars – has a relatively vibrant economy, based on tourism, aluminium and food production. It is far from certain that Montenegrins will vote in large enough numbers to clear the 55 per cent hurdle for independence, with large minorities, including Serbs, who are opposed. At the last election, 57 per cent voted for pro-independence parties, and 43 per cent against.

The latest opinion poll, carried out in November, showed that 43 per cent were in favour of independence, with 31 per cent opposed and 24 per cent undecided. Montenegran diplomats have warned it could be dangerous if more than 50 but less than 55 per cent voted for independence. "You can't have the minority ruling the majority," one said.

Many Montenegrins are frustrated that although they did not join the 1998-9 war against Kosovo they got hit by the same international sanctions. They claim that their country would do better if separated from their troubled partner.

Dragan Kujovic, vice-president of the Montenegrin parliament, said yesterday: “We are a small country, but one with a real basis for fast economic growth but we are held down by Serbia.

As an independent country, without Serbia’s reputation holding us back, we will be able to go a lot faster towards integration with the EU, membership of Nato and relations with the West.”

In Kosovo, the UN envoy Martti Ahtisaari started talks with ethnic Albanian negotiators about the UN-run province’s future. One option is independence, which would reduce Serbia still further.

In a further upheaval, Bajram Kosumi, Kosovo’s prime minister, announced his resignation after Mr Ahtisaari’s arrival, following reports of pressure from within his own party. “I resign in the interests of general progress,” he told reporters.

BLACK MOUNTAIN OF THE BALKANS

• One of Montenegro’s biggest attractions is the Ostrog Monastery, one of the most popular pilgrim sites in the Balkans, built on an almost vertical cliff. It contains the body of Saint Vasilije Ostroski
• Montenegrins rank among tallest people in the world
• At 1.3km (nearly a mile) deep, the Tara gorge is the world’s second deepest after the Grand Canyon
• Mount Lovcen, which rises to 1,749m is known as the “black mountain” due to its basaltic rock, from which the name Montenegro is taken
• Milla Jovovich, the star of Resident Evil and Zoolander is Montenegrin in origin, although she was born in Kiev
• Lord Byron wrote: “At the moment of birth of our planet, the most beautiful meeting of land and sea was on the Montenegrin coast ...”