LONDON -- Plagued by family splits and income tax demands from the government, Queen Elizabeth II may have struck it lucky at last: She could be sitting on a fortune in oil, but the potential oil baroness is unlikely to benefit personally.


The monarch has given a Canadian oilman the go-ahead to drill on the grounds of Windsor Castle for what may turn out to be a giant oil bonanza for Britain. Seismic studies indicate that a geological structure that could contain oil is 300 meters beneath the 900-year-old-castle. Canuk Exploration Ltd. is planning to sink a test well in her garden 32 meters from the castle walls.


"In any other location it would have been tested years ago," said Desmond Oswald, Canuk's managing director. "But nobody previously had the courage."


Oswald told reporters Tuesday up to 100 million barrels of oil could be found. "That is a very large structure. It is one of the biggest onshore."


If that amount were to be found at the site, it could be worth around ?1 billion ($1.5 billion).


A spokesman for Buckingham Palace said, "Permission for exploration to take place is required because it is Crown Estate Land and that was given."


The government will have first call on royalties generated by any find, because the castle is maintained at public expense. But Buckingham Palace said the castle could benefit if the Treasury gives permission.


Windsor Castle, the queen's favorite royal home, was ravaged by a fire two years ago and repairs will cost up to ?60 million.


Windsor mayor Dennis Outwin struck a note of caution.


Outwin, fearful of what could happen to one of the most enduring symbols of Britain, said: "I don't believe you can get 100 million barrels of oil just through a small pipeline. It's bound to lead to Windsor Great Park being turned almost into a second Dallas.


"I feel the queen, whom I greatly admire and who has never put a foot wrong since she ascended to the throne, has for the first time made a bad mistake, or she's been badly advised."


However, Oswald has promised not to turn the monarch's back garden into a 1920s-style oil field studded with derricks. He stressed that the site was purely exploratory and would not affect the beautiful parkland around the castle.


"We would drill the well, the site would be abandoned and then returned to its original condition. We would then look to digging a directional well from a less sensitive area."


He dismissed nightmare visions of Windsor echoing to the constant pump of oil rigs and gas burnoffs lighting up the night sky around the national monument. "People are talking about Dallas in the 1920s when everything was wild. With this, there is no smell, nothing to be seen," he said.


Some oil analysts described his estimate of 100 million barrels as optimistic. "There is only a one-in-eight chance of striking oil or gas in commercial quantities," said a planning officer for Berkshire County Council, which will consider the drilling application on Jan. 4.


But Oswald, a geologist with 40 years experience, said: "The rocks around Windsor look attractive."


The biggest onshore oil field in Britain is Wytch Farm, in a protected rural area of Dorset in southern England. It has 350 million barrels of reserves and produced 98,000 barrels per day in September. Offshore fields from Britain's huge finds in the North Sea produced 2,489,000 barrels a day.


The queen's oil hopes were disclosed just as the royal family was again coming under pressure to live less extravagantly.


The governing Conservative Party has rallied to the queen's defense against suggestions by opposition leaders that Britain could do with fewer royals on the public payroll.


Jack Straw, a senior Labour Party official, said the queen should stay head of state but titled membership of the royal family should be cut from about 40 to 20.


"I think it will hasten the process towards a more Scandinavian monarchy, a monarchy symbolizing a much more classless society," Straw told the BBC.


But Employment Secretary Michael Portillo accused Labour of trying to reduce the monarchy "to some sort of queen on a bicycle." (Reuters, AP)