The New Royal Watch:

By Martha Duffy

PRINCESS DIANA BROKE THE NEWS to her sons at Highgrove, the hated country house she visited for the last time to remove her possessions. Prince Charles sought out the boys at their boarding school to reassure them about his separation from their mother. Then, last Wednesday, British Prime Minister John Major announced the split in the House of Commons in a move timed to get the worst of the press coverage over with before the little princes' Christmas break.

The Prince and Princess of Wales acted wisely on behalf of their sons, because the media coverage was extraordinary. Every paper, broadsheet and tabloid was lying in wait with exhaustive stories. The next morning, the Sun devoted 26 pages to the split. To judge by reaction in the streets, it was a sad day. The fairy-tale marriage was finally over after 11 years, and people were sorry to see the last gleaming gossamer fade into cobweb.

But regret and human sympathy were quickly outdistanced by more practical doubts. Exactly what did the separation announcement, released by the palace, accomplish? "Their Royal Highnesses," it intoned, "would like to stress first and foremost that this decision is amicable . . . There have been no third parties involved, on either side." Well, fine, but the pair have scarcely been able to look at each other, never mind speak, in public, and each has been caught in indiscreet phonefests with a "confidant."

The real boggler was the statement that "there is no reason why Her Royal Highness should not become Queen." That message caused gasps in Parliament. The reaction reflects in part the fact that few believe the Waleses' assurance that they have no plans to divorce. Royal credibility is low on such matters. When Princess Margaret and Princess Anne ended their marriages, the announcements were similar, but divorce followed. The Archbishops of Canterbury and York released a joint statement that the breakup does not affect Charles' future position as head of the Church of England. But that church frowns on divorce. As to remarriage, the stricture is so firm that Princess Anne went to Scotland last Saturday to wed Commander Timothy Laurence.

Tory M.P. John Bowis spoke for many when he said, "It would be absurd to think of two royal processions coming from different directions to the Abbey for a coronation. If it is not possible to have a happy monarch and family, I think we should skip a generation and wait for William." The succession issue lies at the heart of the monarchy; for the institution to survive, it must be stable. If the Waleses pursue other romantic interests, as is likely, the Windsors may reel into even thornier problems than they faced in 1992.

Even the timing of the separation statement was ridiculed. Major canceled a meeting with Jacques Delors, President of the European Commission, just before the Edinburgh summit. Says London University constitutional expert Peter Hennessy: "Royal issues still override all other issues." Anthony Holden, a biographer of Prince Charles, remarks of the announcement, "It just may be that Major is dumb enough to think that the Edinburgh conference would bury it, and the royal family is dumb enough to think that Princess Anne's marriage would obscure it."

The notion that this move will give either Charles or Diana any more private freedom is strictly wishful thinking. If anything, the press will be more relentless. Charles will find a national stakeout on himself and his friend Camilla Parker-Bowles, and tabloid writers are sure to be bolder.

The separation announcement confirms that the tabs were right, a tough fact for the royal family to face. The palace clings to the one thing Charles and Diana undoubtedly have in their favor: both conduct their public lives energetically and responsibly. Now, despite official denials, there will be separate "courts" of competing loyal cadres. But it would be a mistake to think that the estrangement will turn into another Woody-Mia fracas. The couple have great vested interests in common: the throne must be secure for their son.

Diana looks to be the victor in the separation negotiations. Care of the children will be shared, but Diana gets a reported $1.55 million a year, the Kensington Palace apartments, a staff that is mostly her own, continuance of her status as a senior member of the royal family and a life free from Charles' glower. She may have insisted on Major's underscoring her right to be ^ Queen. With the clamor in Parliament, this may be an unrealistic notion. But Diana should not be counted out; her friends say the public has not seen the extent of her portfolio. More and more, she moves center-stage. Quips Holden: "If she manages to pull down the monarchy by mistake, she will be elected the first President of the People's Republic of Britain."

No one is pushing Charles' candidacy for this hypothetical job. In instant TV polls, he was the clear loser in the blame game. He is said to be humiliated by the revelation of the raunchy, so-called Camillagate tapes. His whole life has gone into preparing to ascend a throne that now seems as remote as Camelot.

If the Windsors can weather the next several years, their prospects may improve. Charles and Diana are due for a rough passage; but as their new lives take shape, the direction of the Crown may also become clear. In the meantime, Queen Elizabeth II, 66, must hang in there, as she has for 40 years; her family has not allowed her an easeful old age. Prince William of Wales may be the savior of the monarchy, but he is only 10.

With reporting by Helen Gibson/London