It might be said that the relationship between Great Britain and the United States most resembles that of a parent and child. In 1776, the rebellious American youngster declared its independence from British parental authority and ran away from home for good. The United States grew up to become a strapping adult, while the aging mother country looked on with pride at its offspring's every achievement.

This probably explains why the former estate of George Washington's ancestors, Sulgrave Manor, has become such a popular pilgrimage for both British and American visitors. Never mind that the original Tudor sections of this house in the lush Northamptonshire countryside were constructed in the 16th century by George's great-great-great-great-great grandfather, or that the Washington family sold the manor to a cousin 122 years before the first president-to-be was born across the ocean in Virginia. Roots are roots, and the British display this bit of pre-American history with all the pride of a parent who invites a guest into his child's old room to show off his football trophies.

And indeed there is much of interest at Sulgrave Manor -- located in the village of Sulgrave, seven miles northeast of the town of Banbury in Oxfordshire -- which has become a repository for a small but pertinent collection of Washingtoniana. Most of these items are kept in two cramped rooms on the manor's upper floor. Here the visitor can find Washington's black velvet overcoat, his saddlebags, a lock of his hair, a piece of the elm tree under which he took command of the American army in July 1775, a button from the jacket in which he gave his first presidential address, a handle from his original wood coffin and an alarmingly large oak box in which the president kept his liquor.

Sulgrave Manor last year launched a major expansion program, and the first phase -- a large permanent exhibition called "Soldier of the King," devoted to Washington's early life as a colonial soldier -- opened last spring. But perhaps the most valued object on display at Sulgrave is one of Gilbert Stuart's famous portraits of Washington, which hangs over the fireplace in the manor's Great Hall. The stone floor and oak beam ceiling of this austere room are part of the original structure built by Lawrence Washington, a wool merchant, sometime in the mid-16th century. The surrounding land had once belonged to the Priory of St. Andrew at nearby Northampton. Lawrence purchased it from the Crown in 1539, in the aftermath of King Henry VIII's dissolution of the monasteries during the Reformation. Lawrence's grandson, also named Lawrence, sold the house to a cousin in 1610.

In 1659, Col. John Washington, great-grandfather of George, emigrated to Virginia, probably because of the harsh treatment meted out to his family after the English Civil War. Those who like their history laced with irony will appreciate the fact that in the bitter fight between Charles I and Parliament the Washingtons had been staunch royalists, and after Cromwell's victory the family was dispossessed of its lands. George Washington's forefathers could hardly have anticipated that their own flesh and blood would one day turn republican and lead a revolution against the Crown. The most entertaining part of a visit to Sulgrave Manor is the tour given by its resident curator, Martin Sirot Smith. Smith is a trim, dapper man who serves up the kind of details that make even those who yawned through their history courses listen with interest. He relates that the Washington family appears to have descended from William de Hertburn, who in the 12th century acquired the manor of Wessyngton in County Durham, south of Newcastle. Hertburn took the manor's name as his own, and it later evolved into its present form. This was a happy development, Smith says, wondering aloud whether the Americans would ever have elected someone called George Hertburn as their president.

Next we move to an oak-paneled parlor, part of a wing added to the house during the reign of Queen Anne. The room is filled with furniture of the period, including a table set with blue-and-gold patterned bowls and cups. In those days, explains Smith, tea was drunk from bowls, and the guests slurped the beverage to show their appreciation. The cups were reserved for drinking chocolate, which was served strong and bitter and mixed with cinnamon and curry powder.

In the Great Kitchen, Smith demonstrates the use of the various gadgets and devices that 18th-century homemakers found indispensable. Among them were special shoes with iron brackets attached to the soles, which the servants wore so they could walk unhindered among the piles of muck and garbage that were thrown on the floor and only occasionally swept away. In fact, Smith says, there were no baths or toilets in the house, and people rarely washed themselves.

On that note we move to the bedrooms, the exhibit rooms, and finally back to the Great Hall. Those who wish to stay longer can wander in the garden, or take tea and scones in the small restaurant next door.

Sulgrave Manor (Banbury, Oxon OX17-2SD, England, phone 011-44-295-760-205) is open daily except Wednesdays April through October, weekends only in November, December, February and March, closed in January. Admission is about $2. Michael Balter is a freelance journalist living in Paris. CAPTION: Sulgrave Manor, George Washington's ancestral home in Britain's Northamptonshire countryside.