The long-running campaign to preserve World War II General George C. Marshall's Leesburg home gained fresh impetus Saturday when representatives from Great Britain, led by the British ambassador to the United States, brought with them a letter of support from former prime minister Margaret Thatcher.

The day of celebration and speechmaking in Marshall's honor began with the wail of bagpipes outside the Leesburg courthouse, where a crowd of about 150 gathered to mark the 10th anniversary of the dedication of a statue of Marshall in the courthouse grounds. A U.S. Army color guard, trooping the Stars and Stripes, the Union Jack and the flag of Virginia, led the throng three blocks to Dodona Manor, Marshall's late 18th-century brick Federalist house.

Also present at the celebration were Georgetown and Middleburg resident Pamela Harriman, whose late husband W. Averell Harriman was U.S. ambassador to Great Britain in the 1940s, Lt. Gov. Donald S. Beyer Jr., state Sen. Charles L. Waddell (D-Loudoun), Leesburg Mayor Robert Sevilla and members of the Leesburg Town Council.

Speaking from the front porch of Dodona Manor, Beyer spoke of the close ties between Britain and Virginia, and expressed the hope that the United States and Britain "will continue to be close allies, friends and economic partners in the years to come."

The George C. Marshall Home Preservation Fund, a private group, is seeking to purchase the time-worn house from Marshall's heirs, restore it as a museum and build a conference center on the grounds. The group organized the ceremony to help boost the campaign to raise $3.4 million.

The British contingent, which included the ambassador, Sir Antony Acland, his wife, Lady Jennifer, and an English University professor, Graham Ashworth, who brought Thatcher's letter with him and who, as an expert on historic preservation, is a consultant to the fund, came to support the preservation of what they saw as an important symbol of Anglo-American friendship.

"He has always been held in the very highest honor in my country," Acland said of Marshall. "He was the architect of the close relationship."

The audience sat patiently in the cold as Ashworth, the very model of an English academic with his goatee and half-spectacles perched precariously on the end of his nose, spoke at length of Marshall's achievements during and after World War II, and then read Thatcher's letter that he had brought with him.

"General George Marshall will be remembered by Britain as a man who fought for liberty and democracy in both times of war and of peace," said the letter, which was dated September 1990, while Thatcher was still prime minister, and sent from the prime minister's official residence at 10 Downing Street.

"I am particularly pleased," continued Thatcher's letter, "that the memory of General Marshall should be enshrined at this time, the moment in history when people around the world are rejecting oppression and seeking freedom and democracy, things that he fought for throughout his life."

Echoing those sentiments, Waddell said he believed that Marshall had "laid the groundwork for the triumph of freedom that we're now witnessing in the world."

In August the Town Council gave the preservation fund until the end of March 1991 to raise about $1.2 million toward the $3.4 million needed to purchase Dodona Manor.

No major donations to the fund have been announced since the council set the deadline, but fund President B. Powell Harrison remained characteristically optimistic. "We're going to take title of that property in March," Harrison said, "and that's definite."