By Alistair Smout, Michael Holden and Kylie MacLellan
BALMORAL CASTLE Scotland/LONDON (Reuters) - Scotland's vote on independence this month means Queen Elizabeth faces a division in her kingdom not seen since the days of her namesake Elizabeth I at the start of the 17th century. But some things may not change so much.
Whatever the outcome, Queen Elizabeth is likely to still be queen of Scotland, since most Scots are keen to retain her as head of state even if they vote to go it alone.
After almost 64 years on the throne, Elizabeth is set to overtake Queen Victoria in September next year as Britain's - and both England and Scotland's - longest reigning monarch.
But celebrations then might be muted if Scots vote for independence this Sept. 18, although opinion polls suggest they will not.
The date of the potential split, March 24, 2016, is laden with historical significance: It would be exactly 413 years after the crowns of the two countries were united following the death of Elizabeth I in 1603.
With no children of her own, Elizabeth I's cousin James VI of Scotland became King of England too, although the countries remained separate sovereign states.
In 1707, under the Act of Union, the crowns and parliaments of both countries were formally joined under King James's granddaughter Queen Anne to form the Kingdom of Great Britain.
Idiosyncrasies of that union remain to this day.
When heir-to-the-throne Prince Charles is in Scotland, aides refer to him by his Scottish title the Duke of Rothesay rather than as the Prince of Wales. The title was given to the heir apparent of the Scottish throne before the union with England.
Should Scotland vote for independence, nationalists say Elizabeth, who is 88, would remain Queen of Scotland although they give no guarantee of the monarchy's long-term future.
"Scotland will be a constitutional monarchy for as long as the people of Scotland wish us to be so," the Scottish government, led by the Scottish Nationalist Party, says.
There is no doubt Scotland is close to Elizabeth's heart. She spent much of her childhood there, and her late sister Margaret was born there.
The country is the favorite summer destination for her and her husband Philip, who leave London in August for their estate at Balmoral, often joined by other members of the royal family.
The granite palace, a home for the royals since Victoria's husband Prince Albert bought it for her in 1852, sits in the Cairngorms National Park. With its towers and turrets, it is an impressive example of the Scots Baronial style.
"She absolutely loves it here – she spends four months a year here, and it’s not as though she has to," said one employee at Balmoral, who declined to be named. "It’s run just as it was under Victoria. It’s nice to keep it in the family."
The royals pursue traditional pastimes of fishing and shooting, whatever the weather, and Elizabeth was there with Prince Charles and his sons William and Harry in 1997 when Princess Diana died, leading to demands from newspapers that they return to London.
"One of the problems when Diana died back in '97 was that she (the queen) didn't want to leave Scotland, she was happy there, she didn't want to come down to London," royal biographer Robert Lacey told Reuters.
Tourists are told Elizabeth and Prince Philip are devoted to Balmoral. An exhibition includes features on the queen’s ponies, dogs and custom-made Bentley.
The castle also has a small ballroom, where the royal visitors can perfect their Highland reels.
"If you live in this sort of life, which people don’t very much, you live very much by continuity and tradition," the queen says in one documentary display on her daily life there.
Mary Macleod, a former policy adviser to the queen and now a member of parliament in Prime Minister David Cameron's Conservative Party, said it was the place where the royals had time to switch off from their official duties.
"It is where they relax, it goes back to their childhood," she told Reuters.
Although the queen is assumed to back the union, under her constitutional role she must stay politically neutral.
Her only official comment on the referendum came in May in a message to the General Assembly of the Church of Scotland.
"In this important year of referendum, we pray that whatever the outcome, people of faith and people of good will, will work together for the social good of Scotland," she said.
However, she gave an indication of her views on a split of her realm during a speech to mark 25 years on the throne in 1977 when she referred to referendums on devolved governments in Scotland and Wales, which were later rejected by voters.
"I number Kings and Queens of England and of Scotland, and Princes of Wales among my ancestors and so I can readily understand these aspirations. But I cannot forget that I was crowned Queen of the United Kingdom of Great Britain and Northern Ireland."
Macleod said her actions spoke louder than words.
"It will be something she will be looking at with extremely close interest because historically and to this day she feels Scotland is a very important part of the country as a whole," she said.
Dickie Arbiter, the queen's former press secretary, said Elizabeth had faced the same issue when Australians voted in 1999 against becoming a republic.
He said she took the view then it was for Australians to decide, and it would be the same for the Scots now.
"She's very pragmatic," Arbiter told Reuters.
"If you want to see how the Scots feel about the queen just look at the reception she got at the Commonwealth Games," he said. She was greeted in Glasgow with loud cheers and a rousing rendition of the British national anthem.
Biographer Lacey pointed out that Elizabeth was already head of state of 16 independent nations.
"I don't think that would be a problem for her at all. She's already Queen of Canada and Queen of Australia and Queen of New Zealand and queen of a dozen Commonwealth countries, quite independent of being Queen of Great Britain," he said.
QUEEN OF SCOTLAND?
But amongst those campaigning for independence, there is also a feeling that not only should the union with England be ended, but also the Scottish monarchy.
Kenny MacAskill, Scotland's Justice Minister, has hinted an independent Scotland should hold a referendum on keeping the monarchy, and Dennis Canavan, the chairman of the Yes Scotland campaign who has called a hereditary head of state "an affront to democracy", has said such a vote should take place quickly.
Polls have traditionally shown Scots are less enthusiastic about the royal family than the rest of Britain. However recent surveys suggest they would not want to ditch the sovereign.
A British Social Attitudes survey in June found that 62 percent in Scotland thought an independent Scotland should keep the same king or queen as England.
Post-independence, it would be a matter for Scotland, not what remains of Britain, whether the queen reigns north of the border.
Come what may, for Elizabeth personally, she will still be able to enjoy the palace where she feels most at home.
"Those Highland moors mean a lot to her," Lacey said. "If I could speculate about what she might be thinking, she's thinking whichever way the vote goes, I can still go to Balmoral."
(Writing by Michael Holden; editing by Guy Faulconbridge and Giles Elgood)