I'm beginning to think they really like me for myself,' King George V told a nurse toward the end of his life,'' recalls royal biographer Lady (Elizabeth) Longford.
''I believe,'' the author continues, ''that if the people did not like the monarch . . . that would be the end of the monarchy.''
Lady Longford is one of Britain's most celebrated contemporary historians. Her books include biographies of Wellington, Queen Victoria, the Queen Mother, and now Queen Elizabeth II.
Her new work, ''Elizabeth R.: A Biography,'' was published in America last month. The critical jury is still out on this one, but critics gave a warm reception to Lady Longford's last book, ''Eminent Victorian Women.'' The author points out in her acknowledgments for the new book that researching the Queen was essentially different from any of her earlier projects. It depended not so much on the written record as on conversations, memories, and impressions that have built up into ''something of a recognizable tradition.''
Her research resulted not only in a consideration of the Queen herself, but in thoughts about the role of the monarchy. In a Monitor interview at her country home, Bernhurst, in East Sussex, Lady Longford reflected on both subjects.
Speaking of the interplay between the character of the royal family and perceptions of the institution, she says, ''I think the great popularity of the monarchy now is due in half to the incredibly lucky fact that we have a very good royal family and that the people themselves are worthy of respect. Whatever one feels about the Queen's character and temperament, I don't think anyone - even her most republican critics - ever says that they think she is to be criticized as a person. Now they did that at the beginning of the reign, but not now. The personality of the sovereign now counts far more. A good personality, a popular personality, strengthens the monarchy.''
Lady Longford (nee Elizabeth Harman) started her career with no special sympathies for royalty. She describes herself as politically a ''left-wing moderate.'' As a student at Oxford, she was instrumental in breaking down barriers that impeded women there during the 1920s and '30s. It was at Oxford that she met her husband, Francis Pakenham (Seventh Earl of Longford since 1961 ). Their children, Antonia Fraser, Rachel Billington, and Thomas Pakenham, are all noted writers.
Lady Longford became interested in the monarchy - particularly the reign of Victoria - out of ''sheer curiosity.'' Victoria ''seemed to me wrapped in mystery. I had a hunch that she wasn't a pompous, idle person, who had everything her own way, and to my amazement I found far more extraordinary aspects of her character. Her relations with her husband, Albert, and children were so much more human, so much more tempestuous than one was ever allowed to know. That made me interested in the whole subject.''
To some extent she has had to follow her hunches in writing about the present Queen. Despite the fact that the new book is not an ''official'' biography, however, Lady Longford also had some cooperation from the royal family.
''I was most definitely helped in a very meticulous way by Princess Margaret, '' she says. ''She's efficient and rather scholarly, though she's never had an academic education. She just liked getting down to it. She read the whole of the first draft through, made all corrections - masses of them - in her own handwriting in the margin. . . . She was absolutely frank.''
Princess Margaret ''would ask me to lunch,'' the author explains. ''First time we had a general conversation. Then she read the manuscript. Then she asked me back to discuss all her corrections. Anything I was puzzled about she would check up with her family, so that was incredibly helpful.''
Lady Longford believes she uncovered two new facts as a result of her conversations with Princess Margaret.
''One was that the Queen is not shy. She's reticent and reserved, but not shy. And the other point was that it's been suggested - I did myself in a previous book - that both princesses (Elizabeth and Margaret) had had a very gloomy, cloistered adolescence, which had a rather numbing effect on the rest of their lives. And some people have even gone as far as to say that it prevented Princess Elizabeth's mind from expanding - she was kept in such a cloistered atmosphere that she was not open to new ideas. Well, I was really convinced that this was not true. Princess Margaret did confirm that neither of them felt it. They did not feel sheltered.''
Lady Longford points to two attitudes about the Brit-ish monarchy that relate to its survival. ''Take first the American point of view,'' she says. ''To me it's quite a complex attitude, but very understandable. You only need to read your papers or to be in the States when the Queen is visiting to know the incredible interest that is shown in her and the royal family. And the interest is unique. Americans don't show it in any other . . . royalty.''
The interest stops short of full endorsement, Lady Longford says. ''. . . At the last moment they will draw back. Their democratic side is on the alert, and they don't want to be pushed over into a kind of monarchism which they don't believe in. At the same time they're deeply interested in the Queen, particularly as a person.''
''On the second point of why I think other people in the world are interested , I don't think it's just because she or the monarchy suits us. A good monarchist suits us; a bad monarchy wouldn't. I don't think we'd stick to the institution if it began to show signs of selfishness. But when it's good, I think it's also good for the world as a whole, and people recognize that. A monarchical system, if it works, does make for stability in the country.
''The head of state is entirely separated from the prime minister and from the political parties, and she is definitely above them. As a result she is able to not only represent all the people of this country, but, insofar as other nations like to belong to the Commonwealth, she represents them, too, and is still above their political parties. And that makes for a kind of region of stability in the world, which is a valuable thing.
''Malcolm Muggeridge, whom nobody would immediately think as being a great monarchist, wrote in his diary when Prince Charles was born how much better it was to have a Queen as head of state than a president, who was elected with all the vulgarities involved in the election.
Lady Longford points out, however, that support for the monarchy can never be taken for granted. '' . . . It could vanish very quickly, and the Queen could do nothing about it. For instance, if politics became even more unfair than it is now, you could perfectly well have the have-nots saying they were not part of the nation. . . .''
Lady Longford is adamant, however, that the Queen's role must remain above politics. If she did involve herself in political issues, ''she'd be off the throne before you could say 'Jack Robinson'! . . . She's never done it incidentally. She's been so well trained and educated in her constitutional duties that she's never tried to interfere in any way, but with the Duke of Windsor a lot of people thought it was so wonderful when he visited the South Wales mines and said something must be done, because of their unemployment and their wretched conditions. But the miners themselves, a lot of them, were annoyed and irritated and said this was not his role. He was going beyond his constitutional rights in saying what should be done politically, even though it was to their benefit. It's quite subtle. People are very, very alert to the constitutional limits on the monarch's power.''