Reprinted from yesterday's late editions.

According to Patrick Jay, a castle is "a big thing with points on top."

The 6-year-old son of British Ambassador and Mrs. Peter Jay also was heard to say at an embassy reception Thursday night honoring the forthcoming BBC television series, "Royal Heritage," that he wouldn't want to live in one either. Most of us will never have to make that decision. As Queen Elizabeth's press secretary Ronald Allison, in town for the occasion, put it, "Nobody's building castles these days."

Not like the good days - when home was just a moat away. "Over the drawbridge we went galloping in," explained moderator Sir Huw Wheldon, "with our cameras." His mission? To capture the story of Britain's royal builders and collectors - the palaces, castles, jewels and art treasures - many of them filmed for the first time.

More than 200 guests, including Pamela Harriman, (once married to Winston Churchill's son Randolph), Chief of Protocol Evan Dobelle, President Carter's television adviser Barry Jagoda with "Panorama" TV host pat Mitchell, White House Telecommunications head Rick Neustadt, socialite Ina Ginzburg along with several silver-haired BBC executives and a few silver-tongued ambassadors, sipped cocktails and nibbled cheese puffs before settling into gilt chairs to watch excerpts from the program.

But before the embassy's shimmering chandeliers had dimmed, Peter Jay offered what he called "a few-bland noises" about the British Broadcasting Corp. and joked that it had supported him for many years. Those in the audience who knew that Margaret Jay had worked for the BBC as a producer for many years laughed heartily. Those who didn't know, laughed anyway. It was that sort of evening.

The first excerpt showed Queen Elizabeth touring Buckingham Palace in the same fashion Jackie Kennedy unveiled the White House years ago. At one point the queen explained the origin of a diamond the size of a door-stop. It is part of the Royal Crown of State which, as it happened, Elizabeth had worn that morning. That got a good laugh. She went on to say that when the diamond was presented to the royal diamond cutter, he fainted dead away. After the large stone was cut, what was left "my mother called 'the chips,'" the queen deadpanned.

The managing director of BBC Television, Alisdair Milne, stood behind the projectionist flanked by aproned members of the downstairs domestics who had come upstairs for the show. "I think the royal family did very well," said Milne, commenting on the queen's and Prince Charles' performances. "They weren't paid anything."