Like the parents of so many newlyweds when the wedding's finally over, this tired city emitted a collective yawn last night, and then went to bed early.

Parties and dances had been promised all over town, but by midnight it was so quiet as the day after Christmas. In a way, that's what it was.

The A-list event was the dinner-dance Lady Elizabeth Shakerly, a well-connected noble, gave at Claridge's. The queen came, but people started leaving around 11 p.m., hours before many parties were even close to ending during the frantic days before the wedding.

Perhaps all the royals and nobles were finally tired of spending every lunch, tea, dinner and dance together. The can run out of things to say.

"Good evening," one woman said enthusiastically to a young man at Claridge's last night.

"Good evening," replied the young man, looking blank.

"We were at lunch," she reminded him.

"Ah yes!" he responded. "How nice to see you!" He looked blank as ever.

Nancy Reagan was at Claridge's, as was an impressive lineup of royals:

Prince Phillip. Princess Margaret. Princess Anne. Princess Grace of Monaco, wearing purple. Princess Alexandra. Queen Margrethe of Denmark. And King Olav of Norway.

Once again, Nancy Reagan was on the varsity team. During her frantic week of partying here, only once was she off. That was for yesterday's wedding breakfast, held after the ceremony at Buckingham Palace for 120 close family members and friends. Nancy Reagan went to a lunch given by Prime Minister Margaret Thatcher instead.

Last night, she wore a long flowing chiffon-like green gown. "Ohhhhhhh," she said of the wedding to a reporter, "it was just beautiful." That was it. She sat at the queen's table. Protocol Chief Lee Annenberg sat nearby talking to Princess Margaret, who, rumor had it, cooked up the idea of having scrambled eggs and bacon and kidneys at a dinner dance. She likes that.

Everybody more or less nattered away about the wedding.

Over at Annabel's, the nightclub that remains London's high-class version of Studio 54, ABC news chief Roone Arledge did his own nattering.

"I've tried to sit and think," he said, "why the hell are we over here covering this?"

He never really came up with an answer, but did offer: "If you believe that this family represents something special about Britain, it's a unifying thing. They've passed a national referendum to believe in Santa Claus."

Annabel's was also quiet, although actress and former girlfriend of Prince Charles Susan George did turn a few heads when her blond one walked in.

The scene was the same at Tokyo Joe's, the new "in" spot for apprentice jet-setters. Dull. "Many of these people were at the wedding," said Dai Llewellyn, whose brother Roddy once hung around with Princess Margaret, "and now they are relaxing." A sad red, white and blue wedding cake sat in the corner.

Hotels offered special Lady Diana and Prince Charles menus ("delice de sole 'Prince Charles'" at the Hilton), but at 10 p.m. the place was half full. "Well," offered the assistant manager, "they went on a honeymoon, you know."

And Nancy Reagan finally went home. After a week that included five dinner parties, five luncheons, two receptions, one ball, one polo match, one wreath-laying, one fireworks display, one social service stop and one royal wedding, she is scheduled to arrive in Washington at 11:30 this morning.

On her last day in London, the British newspapers continued to plague her.

Yesterday, for instance, both the liberal-leaning Guardian and the conservative London Times took swipes.

The Guardian ran a picture of Nancy Reagan and her husband over the caption: "The once and future king -- and queen?" Then in a spoof in yesterday's paper, they continued: "Her refusal to curtsy to anyone -- announced before she left Washington -- was not an egalitarian gesture, but was part of preparing her for her new role. Her need to try harder on this score was emphasized by her reference on news at 10 on Tuesday to her meeting with the king and queen of England."

And from the Times: "Mrs. Reagan, whose visit has occasionally assumed the aspect of a rewarding but somewhat exclusive affair with the American press corps, coincidentally conducted on British soil, was able to penetrate her security cordon a little more successfully yesterday."

Still, the crowds seem to like her -- or are, at least, fascinated by this American first lady they keep hearing is so glamorous. Last night as she left Claridge's, a young girl cried out, "Nancy! Nancy! Can I have your autograph?"

She could.

A few last items from the first-lady trail:

Nancy Reagan sat in the sixth row of St. Paul's Cathedral about halfway across. This was a very good seat. There'd been speculation that she'd asked for the front row, and also that she'd sit halfway back.

Raine Spencer, who's been dubbed by the press as Diana's "wicked stepmother," sat in the fourth row with the family. This proved the gossips wrong, who said she'd really be in the far, far back.

Joe Canzeri, a member of the first lady's entourage, came bouncing out of Claridge's last night to say to one American reporter. "We won the tax package, 335 to 80. Amazing." In fact, the vote was 238 to 195.

"Yeah, but what about William Casey? asked the reporter, shifting quickly into the Washington mode.

"He's okay," said Canzeri. "We'll make it."

You could tell the trip was over.