Montenegro will vote on independence on May 21, parliament decided Thursday, with the referendum to settle the fate of the last remnant of the former federal Yugoslavia. The assembly unanimously backed the date proposed by President Filip Vujanovic, a day after it passed a law laying out the rules of the vote. The stage for the referendum was finally set after years of wrangling between the "sovereignist" authorities and opponents that favour continued union with Serbia. Under a European Union-brokered deal, the 460,000 registered voters will respond to a question asking whether they support a fully independent Montenegro. If at least 55 per cent of those voting are for independence, Podgorica would end the already loose and largely dysfunctional union of Serbia and Montenegro. The EU welcomed the assembly's approval. The broad support for the referendum law is "a good basis for a transparent and democratic process that has Europe's full support," EU foreign affairs chief Javiar Solana said in a statement. The EU presidency, currently held by Austria, issued a statement saying the referendum now has legitimacy and urging all political forces in Montenegro to ensure that "the organisation and the implementation of the referendum is accepted in all of Montenegro."