What Julian Grenfell, chief speech writer at the World Bank, writes all day at his office is so different from what Julian Grenfell, the novelist, scribbles in his dining room at night that if he ever got his papers mixed up, his publisher would probably fall asleep and the president of the World Bank would blush with embarrassment. Either way, Grenfell would probably be fired from both jobs.

Here's what he writes during the day:

Resort by the United States to protectionist measures would not only intensify the financial problems with which the developing nations are struggling; it would also be an ineffective response to this country's own current-account deficit.

-- from "International Trade and Global Economic Growth, The Critical Relationship," an address before the Economic Club of Detroit by the president of the World Bank.

And here's what he writes at night:

They had sat for a while, cuddling close to one another, on the stump of a felled tree, gazing across the rippling water, following the silvery shaft of reflected moonlight to the distant bank and the Argyll hills looming black and deep violet against the clear night sky.

"I want to make love right here," Margot had whispered in his ear.

-- from "Margot"

He never takes work home from the office.

"I wouldn't be able to sit down in this office and write dialogue," he says, "any more than I would be able to sit down at home in Georgetown and write speeches. I keep the two absolutely separate."

He revels in it.

"I've always loved a life of contrast," he says. "I'd be very unhappy if my life was made up of just round-the-clock concentration and my mind on one particular narrow frame of problems."

He is British-born, a member of the House of Lords, the third baron Grenfell of Kilvey; he was educated at Eton and King's College, Cambridge (where he was president of the Cambridge Union, the debating society).

He is also highly unconventional -- at least, by the standards of his pedigree -- doesn't use "Lord" on the nameplate over his office door, and actually works for a living.

"I came from one of the members of the peerage who was at the very low end of the wealth scale," he says, sitting in his World Bank office, which includes photographs of Hubert Humphrey, Haile Selassie, and Muhammad Ali. He is 49, his manner is quiet but not stuffy, and he's dressed in navy blazer with a burgundy silk handkerchief sticking out of the pocket. He has a sort of upper crust Alec Guinness look -- a tailored face.

Grenfell's first novel, "Margot," (published by Freundlich Books) has yet to make him rich. "One of the things one learns about being a first novelist is it's rather like watching the trains go by with all your money on board," he says. "It goes from one publisher to another or an agent."

The novel chronicles the steamy loves and adventures of the beautiful young daughter of a senior American diplomat, starting on the eve of her engagement to an aristocratic English officer in England during World War II. For the next 550 pages, Grenfell traces Margot Moore's triumphs, tragedies, babies, career (fashion model in Paris), and sexual passions through the war and afterwards, across England and France.

Tolstoy it is not. A made-for-television movie it could be. (He has an agent looking into that.)

Grenfell proudly says that the history in the book is painstakingly researched. In fact, he set out to write a historical novel.

But what's getting him the attention is the explicitness of his portrayal of his heroine's lustier moments. They are only a small part of the book -- but they're very saucy.

"This may sound rather an odd thing to say, but I'm a fanatic about accuracy," Grenfell says. "I went to a great deal of trouble to be sure that when I was saying that de Gaulle was having lunch at the Connaught Hotel on a certain day, that he was indeed in London . . . If I'm going to be explicit and accurate about the political and historical background of the time, why can't I be explicit about the way people behaved? So I did it and I don't regret it."

His editor was pleased. His family gave it mixed reviews.

"Some members of my family in England are rather appalled by it. I have an uncle who actually thought it was splendid, but then he's a very good writer . . . A few cousins and aunts thought it wasn't the sort of thing they were going to hand out as Christmas presents."

While he was in London this fall promoting the book, he saw his friend, Lady Antonia Fraser, the respected historical author whose latest best seller, "The Weaker Vessel," is a history of women in 17th-century England. "We were having a giggle," says Grenfell, "about how different our books were and whose books were on what shelves."

The London press is amused. "They write, you know, 'Pornographic Peer,' " says Grenfell, who says he told London television and radio interviewers, " 'The fact that it's written by a peer and that you're commenting on this suggests that you think members of the British peerage shouldn't know anything about sex.' I said that hereditary peerage would have been dead long ago if we'd known nothing about it."

Nonetheless, those scenes are "actually quite embarrassing to write, in a way," he says, "because you've got the feeling of being a voyeur."

By his own admission, he's a rather unconventional lord even without the steamy novel. He believes a firstborn daughter in a family should be allowed to inherit the title ("I'm a feminist") and he criticizes the hereditary system in general. "I don't really even believe much in the system that allows me to sit in the House of Lords," he says. "I've never really believed that just because one was born the oldest son of a peer, that gives you the right to legislate." However, while the system exists, he loves to be part of it.

But Grenfell says his first priority, before his writing and his politics, is his World Bank job. His colleagues there "have been, on the whole, amused, quite kind" about the book, he says. But he never discusses the book with his boss, the president of the World Bank, A.W. Clausen. "We have a lot of things to talk about," Grenfell says. "I didn't want to waste his time saying, 'Hey, I've written this book. You ought to read it.' "

In fact, Clausen declined to comment on Grenfell's novel. "We're in a situation here of some 6,000 people, roughly 100 nationalities . . . many of us produce books," said Martin Koelle, acting director of information and public affairs at the World Bank. "Most are of a different nature from the one Julian produced. But it wouldn't be appropriate for Mr. Clausen to comment on one staff member's book."

However, Koelle said that Clausen "was quite amused about the book. It is a bit out of the ordinary. Not the normal books coming out of the pens of World Bank staff members."

Grenfell, who has worked at the bank for nearly 20 years, has been Clausen's chief speech writer since 1983. Grenfell also gives his own speeches, often on economic development in the Third World.

"Occasionally you will get somebody saying, during question time, 'Do you think all the commercial banks in the country are going to go down the drain because the loans in Latin America are never going to be repaid?' You deal with that one and then get somebody coming in and saying 'Where can I buy your book?' "

Still, there have been those moments when a thought about dialogue crept in during World Bank hours. When he was the World Bank's representative to the U.N., he would spend a month each summer in Geneva for meetings. He toted a typewriter and, during breaks in the meetings, strolled along the lake thinking of Margot.

"There were a few occasions in New York when one was attending long meetings at the General Assemby when one's mind would wander . . . maybe a little bit of dialogue would come into one's mind and one would make a little note," he says, smiling. "The delegate next to me would lean over and see what I was writing."

Grenfell's first career was in English television. "I was anchorman of the Sunday evening religious discussion program," he says. "The first time I ever discussed the World Bank was on a religious program where we talked about moral responsibilities toward the Third World."

In 1964, he came to the United States to cover the presidential election for British television and heard more about the World Bank from friends. He returned a year later to work there, "to write speeches, maybe help make some movies about the bank, and I got so engrossed by what it was all about and I liked Washington so much that I decided to stay." Grenfell has been the World Bank's deputy director of the European office in Paris, and also has served at the U.N. and held various positions in the Washington office.

Grenfell does his writing in the Georgetown house he shares with Leezee Porter, the Democratic cochair of the Women's Campaign Fund. "I loved it," she says of the book. "A lot of people said it was their first real comfortable glimpse into British society." (Grenfell is divorced from his first wife, separated from his second, and has three children.)

Now, he spends early mornings, late evenings, and weekends working on his second novel, which is set against the backdrop of the 1936 Olympics in Nazi Germany.

"It doesn't leave much time for social life," he says, "but I get around. Living in Washington, one of the nice things is it's a much calmer life for a writer. In New York, life was so frantic. You were always running around. Here, people understand if you want to stay in and write."