Britain and the States: TV probes the special link. Host David Dimbleby talks about new series and its aims

``Margaret Thatcher and Ronald Reagan have established the closest relationship of any American president and British prime minister in history,'' said David Dimbleby, the BBC's major political commentator. ``However,'' he added, ``the Churchill-Roosevelt relationship will turn out to be far more significant in the long run.'' Mr. Dimbleby was in New York to interview inside observers of recent history for his seven-part series, ``An Ocean Apart,'' which delves into the changing relations between the United States and Britain from the World War I to the present day. (It starts airing on the Public Broadcasting Service on Monday, 9-10 p.m.)

Like many British hosts of PBS series, Dimbleby has discovered that a little promotion goes a long way in selling the book that invariably accompanies the series - in this case, the companion volume he wrote, with the same title as the series.

Mr. Reagan and Mrs. Thatcher - closer than Roosevelt and Churchill? Can that really be true?

``In this series, we investigate both those relationships,'' Dimbleby explains. ``Of course, the stress on Roosevelt and Churchill was far greater, the issues much larger. And the characters were much grander. But it was never forgotten by either Roosevelt or Churchill that Roosevelt was an anti-colonial Democrat and Churchill an old-fashioned high-Tory colonialist. Therefore, their political instincts were diametrically opposed. Neither forgot it, and they had to override that to achieve what special relationship they did manage to achieve.

``But there was no natural affection. In the series, Churchill's secretary reveals that Churchill once said: `Never did a man study the whims of his mistress as carefully as I studied the whims of Roosevelt.' It was a deliberate plan to flatter and cajole and eventually persuade, whereas with Thatcher and Reagan you have an instant collusion of identical political views. They're far closer than Churchill and Roosevelt ever were, but, of course, in circumstances that, while troubling, are not on quite the same gigantic scale as conducting a world war.''

Dimbleby, a ``presenter'' of current-affairs programs on BBC, is the eldest son of Richard Dimbleby, the BBC's chief correspondent and commentator during World War II. The elder Dimbleby was known to millions of Americans as the voice announcing the coronation of Queen Elizabeth II. His son has been the presenter for ``Panorama,'' ``24 Hours,'' and ``This Week Next Week,'' as well as host of ``The Dimbleby Talk-In.''

In researching the series, Dimbleby and Cambridge historian David Reynolds tried to concentrate on people on the periphery of history talking about recent events as history, rather than going to Thatcher and Reagan, for instance, to ask them to talk about themselves.

``We got a nice interview with Richard Perle [US assistant secretary of defense from 1981 to '87] about Mrs. Thatcher's visit to Camp David, for example. He told us they spent a lot of time talking about things like the Strategic Defense Initiative. The great thing about having President Reagan confer with PM Thatcher was that she was the only person the President would listen to on some issues. I think when he came into office he was thrilled to find a fellow spirit in Mrs. Thatcher, one who believed, as he does, that Russia is indeed an evil empire intent on world domination and must be stopped. At that time, most of Europe didn't agree. So there was a political reason for their instant closeness.''

Then Dimbleby adds seriously, but with a mischievous twinkle in his eye: ``But I always assume that one great advantage Mrs. Thatcher has is that she enunciates clearly, and you can certainly hear what she has to say. So if you're slightly hard of hearing, she gets through to you.''

Dimbleby says he discovered some very revealing - and potentially controversial - facts about the level of British-American cooperation during the Falklands war. ``It's a superb example of the special relationship between our two countries really working. No questions asked from the beginning.

``In looking at the records, we found that right through that period - despite what Reagan and Haig and Kirkpatrick were saying publicly about being evenhanded - from the very first day virtually no kind of help was refused. We paid for it, but we got it. [John] Lehman gave us a good interview in which he says that even to this day he doesn't believe the South Americans realize quite how heavily committed America was to Britain's success.

``Without it, Britain would have had to withdraw from the Falklands war quite early on. It is impossible to think of a more perfect example of the relationship that we British and you Americans have, different from any other relationship that the US has with any other country in the world.''

Dimbleby says that, despite the Falklands help, Thatcher was furious when the US went into Grenada without consulting Britain, since Grenada was a Commonwealth territory. According to Dimbleby, she phoned Reagan at 4 a.m. to protest. But that didn't prevent her from allowing the use of bases in Britain for the Libyan attack, despite the fact that she knew there would be strong opposition in Britain.

``Many people consider it a partial payment on the Falklands debt,'' he says.

Dimbleby does not believe that America is on the road back to isolationism. ``That was a luxury only possible at one time because the British Empire was keeping the peace in different parts of the world. It's clear now that, if the US wants to protect its economic interests, it has to maintain a physical and perhaps military presence in many parts of the world.''

What does Dimbleby want his series to accomplish?

He takes a deep breath. ``It's difficult to say this simply. But I'd like the series to demonstrate to American and British viewers alike that Britain and America are more than just close friends, more than just old allies. We have a much more complex relationship. And the story of that relationship - particularly during this century - is the story of America's rise as well as of Britain's decline. The two events are interconnected. Without one, the other would not have been possible in the time it happened.

``There is intense rivalry, but the miracle is that, without firing one shot at each other, power has passed in one generation from one to another. Basically, the series makes it apparent that the mantle of power - the domination of the free world - has passed from Britain to America in our lifetime.''