BOOK REVIEW : Comedy of Conflicts, English-Style : TITMUSS REGAINED <i> by John Mortimer</i> Viking Penguin $19.95, 281 pages

While John Mortimer’s earlier novel set in England’s unspoiled Rapstone Valley isn’t a prerequisite to your delight in “Titmuss Regained,” knowing these particular characters from adolescence can double the pleasure.

Starting here and now with “Titmuss Regained,” you’ll meet Leslie Titmuss as a mature and successful politician, recently widowered by his reckless wife, Charlotte, who was run down by a lorry during a nuclear disarmament demonstration. In the opinion of Lady Grace Fanner, Charlotte’s mother, her daughter’s death “at least caused the terrible Titmuss extreme embarrassment. . . . Having a wife who went to bomb protests was worse than tucking up with a tart in Mount Street.”

Said to the eager young vicar paying his weekly duty call, that remark tells you all you need know about the dying Lady Grace, as well as suggesting that Titmuss was not her choice for son-in-law.

Lady Grace, like the unfortunate Charlotte herself, would have preferred Fred Simcox, son of the previous rector, but when Charlotte suddenly needed a husband, the ambitious Titmuss saw an opportunity to acquire a necessary touch of class. That never happened, and Leslie Titmuss, secretary of state, is as common as ever, though far more adept at concealing it.

As this book begins, he is attempting to buy Rapstone Manor, left vacant by the demise of Lady Grace. Not only is the Manor conveniently situated in his home district, but as the village squire he’ll be able to lord it over the county types who made his youth a misery. Though his mother was a housemaid and proud of it, Titmuss has grown up Conservative, exploiting his working-class background in speeches but convinced that what’s good for business is good for the country.

The picturesque Rapstone Valley has fallen on hard times, and Titmuss supports a plan to build a vast housing development in the area, a satellite community appealing to young professionals priced out of the London market and even more to the locals eager to profit from the sale of their land. The builders promise that the proposed new town will be virtually invisible--”an up-to-date version of the lost Atlantis which had that mythical city’s talent for disappearing tactfully from view.”

Determined to preserve their last vestige of England’s bucolic tradition, the more sophisticated Rapstone villagers have organized to Save Our Valley, enlisting not only Titmuss’ archrival from boyhood, Fred Simcox, but eventually Titmuss’ brand new wife, the altogether charming young widow Jenny Sidonia, for whom he has bought the manor.

Will the man who championed the housing project continue to press for it once his dining room overlooks its car parks? Will the developers still be able to count upon him when traffic chokes the narrow country roads and taxes must be raised to provide all the public utilities required by a burgeoning population? Having finally become The Squire, will Leslie Titmuss happily preside over the liquidation of his little fiefdom?

These questions are asked indirectly, in splendidly satiric chapters presenting a surprisingly broad spectrum of contemporary English types. Though the county elite in their tweeds and wellies are well and truly represented at the S0V meetings, the finest comic moments are supplied by the young bureaucrats in Titmuss’ department, whose intrigues provide commentary and counterpoint to the essential story of a man caught between public and private interest.

Ever considerate of readers who might not be immediately captured by British political maneuvering, Mortimer has included an incidental and beguiling mystery to give his tale an added dimension.

By the end of “Titmuss Regained,” you’ll know why the ultraliberal and elegant old rector of Rapstone, Simeon Simcox, bypassed his own sons to make Leslie Titmuss his heir, not exactly setting these particular events in motion, but certainly keeping the momentum going.

Next: Carolyn See reviews “Because It Is Bitter and Because It Is My Heart” by Joyce Carol Oates.