By Ian MacKenzie
EDINBURGH (Reuters) - Scotland will introduce a bill within nine months on holding a referendum on independence, First Minister Alex Salmond said on Tuesday, paving the way for a vote that could result in the eventual breakup of Britain.
Salmond, aiming to end the 305-year-old union with England, wants a vote on independence in the second half of 2014, though he has yet to thrash out an agreement with the United Kingdom government in London on how the question will be worded.
"Work will get under way in earnest on the Referendum Bill, laying the groundwork for Scotland's most important decision in 300 years," Salmond, who leads the Scottish National Party, told the opening session of the Scottish parliament in Edinburgh.
A Scottish vote for independence would undermine the foundations of modern Britain which comprises England, Scotland and Wales. Northern Ireland and Britain make up the United Kingdom.
Salmond, a former economist with a penchant for clothes with a traditional tartan pattern, said he expected to complete talks on details of the referendum with UK Prime Minister David Cameron within a few weeks.
He said the Referendum Bill - the first legislative step towards a vote - would be introduced in the current parliamentary year, which in Scotland ends in May or June.
It will say who is qualified to vote, and will spell out the question or questions that Scots will be asked and deal with procedural issues such as how the votes will be counted.
Salmond would like to include a third option to give Scotland added powers in the event of a vote against independence, but the UK government in London wants a straight "yes" or "no" vote on independence.
A host of questions on everything from the UK nuclear deterrent - its submarine fleet is based in Scotland - to ownership of the estimated 20 billion barrels of recoverable oil and gas reserves remaining below the UK part of the North Sea remain unresolved.
Salmond, who is viewed with cautious respect in London, has angered the Catholic Church with a plan to make Scotland the first country in the United Kingdom to approve same-sex marriages.
"Our Marriage and Civil Partnership Bill will enable same sex couples to get married, and will allow civil partnerships to be registered through a religious ceremony," Salmond said.
His party won a majority in Scottish elections last year and under the devolved system of government, the Scottish parliament has control over health, education and prisons. Scotland also has its own legal system.
The bulk of its funding comes from a 30 billion pound grant from the UK government, but Salmond has said an independent Scotland would be entitled to the lion's share of North Sea oil revenues.
The Scotland Act 1998 gives the Scottish parliament the power to pass laws on a range of subjects and to raise or lower the basic rate of income tax by up to 3 pence in the pound.
The UK government in London controls foreign policy and defense, but Scotland has many of the trappings of an independent nation - its own flag, sports teams, culture and a history of achievements in science and literature.
(Additional reporting by Stephen Addison; editing by Tim Pearce)