THERE WAS a time, not too long ago, when the most exciting stamp news out of Great Britain was the selection of a new view of the reigning monarch for the stamps of the Commonwealth.

The sun never set on the British Empire in those days and the postage stamps of the Commonwealth states rarely varied, save for the view of a local landmark that was dutifully engraved along with the visage of the king or queen.

That all changed in 1964 when British Postmaster General Tony Benn, still considered controversial by some collectors, decided that Great Britain should issue what the British call "special stamps."

Benn's decision to plunge the United Kingdom into the brightly colored world of commemorative stamps probably was as earth- shaking to some collectors as anything Britain has done since issuing the "Penny Black," the first postage stamp, in 1840.

Today Britannia still reigns as one of the most popular countries among U.S. collectors, but a stamp from Great Britain might celebrate Peter Pan, actor David Niven, contemporary architecture, endangered wildlife, or Halley's Comet.

Last month there was a set of four stamps commemorating modern pottery and earlier this year sets marked the glories of the Victorian age and Scottish heraldry.

"I do dispute that we do anything trivial," said Keith Fisher, head of stamps and philately for the British Post Office, in an interview this week. Britain did reduce the number of stamps it was issuing after an outcry that Benn's policy initially led to too many "specials."

Britain now typically limits itself to about eight commemorative sets each year, Fisher said. One set is reserved for Christmas stamps and another is devoted to the topic picked by the European postal organization for a common issue.

That leaves only six subjects per year to be selected from among the 300 annual requests, well under the 1,500 the U.S. Postal Service receives each year.

Even though the BPO is a public corporation, the Crown still has a say over new stamps. Once a design for a new issue is approved by the BPO, it goes to Buckingham Palace for the Queen's approval.

"She takes a close interest in the stamps and if she makes any suggestion, it is appreciated," said Fisher.

Next year promises to keep HRM busy. The BPO has announced it will issue stamps celebrating children's verse, sports, transportation, the 400th anniversary of the translation of the Bible into Welsh, as well as two issues close to the grand old days of the Empire. Those stamps will celebrate the bicentenary of the settlement of Australia by Europeans and the 400th anniversary of the defeat of the Spanish Armada.

While some of the recent ideas out of London trouble British traditionalists who long for the days when British stamps featured a stern-faced monarch, Fisher said the BPO has a deliberate policy of insuring that each year's program includes stamps with special appeal to youngsters. This year's Christmas set, the Peter Pan stamps and the children's verse set for next year all fit those criteria, he said.

The BPO believes it has an obligation to develop a new generation of stamp collectors and thus regards those stamps as "very important," he said.

That may explain the disenchantment with which some longtime collectors view some of Britain's new issues. Richard Welter, a Fairfax dealer who specializes in British Commonwealth stamps, says he stopped collecting about the time of Benn's decision and now does not regularly stock new issues from Great Britain for his customers, preferring the days when George V or George VI was on every stamp.

Gloucester, Virginia dealer Dan Warren, another British-stamps specialist, also expresses a fondness for BPO's regular stamps, which he calls "models of simplicity."

"Some of the designs, to me, seem to go overboard a bit," says Warren. And Welter says he is delighted that Great Britain has not gone the way of some of her colonies, which will issue "anything" in their bid for sales to collectors.

Some things British have remained the same and both Welter and Warren say they believe Britain is more thoughtful about its new stamps than the U.S., and that its commemoratives, as a result, are often more attractive.

Fisher also proudly notes that the two hallmarks of British stamps have remained.

The United Kingdom is the only nation allowed by the Universal Postal Union to issue stamps without the country's name, and its "special stamps" always include the monarch, albeit now often in a small silhouette in a corner of the stamp.

Stamp Show: The 16th Annual Washington International Lions Stamp Show will run from 10 to 6 Saturday and 10 to 5 Sunday at the Greenbelt Armory, 7100 Greenbelt Rd., Greenbelt. $1 for adults, children free.

Bill McAllister is a member of The Post's national staff.