LONDON, OCT. 28 -- If it's October, there must be rumors of trouble in the marriage of Britain's Prince Charles and Princess Diana. October is the month Charles spends fishing and hunting at Balmoral, the royal family's Scottish estate. Diana, who reportedly finds the place boring, usually stays at home.

Most years, the two manage to commute for a night together every week or so. This year, however, has been different. The published 1987 September-October royal calendar appears to indicate that, up to last Saturday, the prince and princess managed to spend 35 straight nights in Britain without sharing a bedroom.

Further cross-checks by palace watchers -- akin to Kremlinologists' attempts at fathoming the political or physical health of a Soviet leader -- reveal that the world's most photographed couple, whose public lives are made up of heavily reported civic functions, did not make a single appearance together between Sept. 16 -- when they both took their younger son, Prince Harry, to his first day at school -- and Oct. 21.

As a result, the usual October rumors have taken a quantum leap to what the Daily Express newspaper yesterday called "The Unthinkable Questions. Will It End in Divorce? Who Will Get What?"

Henry VIII aside, are they even allowed to get divorced? That question was neatly disposed of by the reigning authority on such matters, something called the College of Arms. "The prince could get divorced in the normal way ... without any special permission from the queen or Parliament," said a spokesman.

Talk of separate bedrooms and marital disagreement are one thing. But the specter of divorce seems to have moved the entire issue out of the category of celebrity gossip and into the higher realm of constitutional monarchy. Queen Elizabeth II is, after all, head of state of Britain and a substantial scattering of former colonies around the globe. Once she dies, Charles is due to take over.

Speculation about the ups and, more often, the downs of the royal couple -- a seemingly mismatched pair with a 12-year age gap and widely divergent tastes in everything from friends to music -- is staple fare for Britain's "popular" tabloid press. Such stories usually blame Diana's allegedly flighty and flirtatious ways, only occasionally fingering the staid and serious Charles as the culprit. But in recent days, even such widely respected British newspapers as the Guardian, the Daily Telegraph and The Sunday Times have been moved to comment.

"Evidence that all is not well goes beyond the usual tabloid hype," said last Sunday's Times. The queen, the paper advised, was about to put her foot down. "It is said that her majesty will impress upon them that whatever the state of their marriage, Charles and Diana must avoid lengthy periods out of each other's company," the paper said. "To put it crudely, Charles will be told that he must spend more time 'under the same roof' as his wife."

Getting at the truth of such matters is all but impossible, since none of the principals will speak of it publicly. Asked today whether it had any comment on the rift reports, the Buckingham Palace press office said "none at all."

Most respectable royal-watchers dismiss the divorce reports as absurd. "It's nowhere near that level," said James Whitaker of the Daily Mirror, "and they both have got far too much sense of duty and sense of propriety to ever allow it to get that far."

Divorce "will never happen," said Harold Brooks-Baker of Burke's Peerage, the consummate reference guide to the British aristocracy since before Queen Victoria. "Constitutionally it would be totally unacceptable, and more importantly, as arranged marriages go, this one is 100 percent secure."

"There's absolutely nothing in it," said royal-family correspondent Dickie Arbiter of London's LBC radio.

In an interview Tuesday, Brooks-Baker warned that constant press scrutiny of the marriage could destroy the royal family. "The country is close to a constitutional crisis," he said, over a "problem ... created by the press."

"When Charles and Diana married," he said, "the press made this up to be the love match of the century ... This was a semiarranged marriage which pleased all members of the royal family at the time. Today it is a very workable marriage in which there is no problem of any importance. The prince and princess of Wales clearly have a great respect for each other and for the job each is doing."

Talk first took a serious turn about two weeks ago after the realization that the two hadn't been seen together in a while gave rise to another of the regular waves of marriage-trouble reporting. By Oct. 20, however, it had reached a point that prompted Diana to flare out in public.

While on a visit to a Middlesex nursery school, the princess turned her back on photographers, mumbling, "I don't see why I should help the press out. They don't do anything for me."

Then, beginning a conversation with the school staff, she reportedly remarked that son Harry had a cold and that "I didn't have a very good night's sleep because he was climbing into my bed." That very morning, as she had left for the school, Diana said, Harry had clung to her and said " 'Mummy, don't leave me.' I felt a little guilty."

"You should let his dad look after him," teacher's helper Alita Connell said; then she asked, "Is there any truth in what the papers are saying?"

"What do you think?" Diana replied, before turning away.

The next day, in what some commentators said was a hastily arranged meeting to disprove the rumors, Charles flew down from Balmoral to pick Diana up at a Royal Air Force base outside London for a visit with flood victims in Wales. Pictures of them together, dressed in rain gear and looking concerned, were featured prominently on all television news programs.

But the national sigh of relief came a moment too soon. Rather than returning home with his wife, Charles dropped her back at the base to return alone to their Kensington Palace apartment here while he went back to Scotland.

"Doesn't that tell you a lot?" asked one senior member of the royal press corps. "Forget the hype. Forget the tabloids. Just remember that basic fact. He didn't even go back to KP ... He just got back on the plane."

The intensity of the speculation rose to even higher levels last weekend. On Saturday night, Charles showed up at Highgrove House, their country home in Gloucestershire, with a bouquet of flowers and toys for the children. But by midafternoon the next day, Diana was seen leaving the house in her Jaguar XJS, driving back to London alone.

Arbiter, a reporter who sticks to more traditional coverage of the monarchy, said it was ridiculous to interpret the family's comings and goings as evidence of personal preference. Charles' return to Balmoral, he said, "wasn't arranged overnight." Even there, the prince has commitments, both social and official, that are decided months in advance. "Just because there are floods in Wales, you can't call around and say it's canceled, you can't come."

Charles and Diana are not scheduled to make another public appearance together until next week, when they undertake an official visit to West Germany. Meanwhile, the press continues to draw its own conclusions.

For papers like The Sunday Times, the moral of the story is that the royal lot is a sad one. "It is {their} misfortune ... that there is no such thing as privacy," the paper said. "The royals are in the paradoxical position of not being 'allowed' to have personal problems, and of being unable to hide them if they do."

Not everyone was so sympathetic, however. The tabloid Sun, perhaps resentful that the royal family seemed unwilling to sing loudly enough for its supper, took on Diana's question -- "What's the press ever done for me?"

"The Sun can answer her loveliness in one word -- EVERYTHING," the paper editorialized. "The newspapers have made her one of the most famous women in the world. They have given her an aura of glamour and romance." Without the press, the Sun said, "the entire Windsor family could soon become as dull and commonplace as the rulers of Denmark and Sweden. Were that to happen, people might begin to ask what is the point of having royals at all? Including lovely Princess Di."

Meanwhile, in a tour today of job training workshops in Manchester, Charles seemed unrattled by the commotion and spent 90 minutes chatting with crowds of local people who had waited hours to see him. He arrived there by train after reportedly spending the night at Kensington Palace with his wife.