John Mortimer Develops a Case of Love of Country : Writing: Former barrister wages a fight for slow growth in Britain with his satirical novel ‘Titmuss Regained.’

The battles in favor of slow growth and against developers and the despoliation of countryside and cityscape is not only an American phenomenon. In a lethally satiric new novel, “Titmuss Regained” (Viking, $19.95) John Mortimer charts the valiant struggle to save the lovely if fictional Rapstone Valley from becoming a new town with a small shred of its natural woodland preserved as a theme park.

The Rapstone Valley sounds much like the lovely Oxfordshire countryside around Henley-on-Thames, where Mortimer lives and where he was not long ago involved in a successful campaign to stave off a development.

“The papers at home like to call me a champagne Socialist or a Bollinger Bolshevik,” Mortimer said over lunch during a stop on a book tour. He is probably best known to American audiences as the creator of Horace Rumpole of the Old Bailey, the marvelously irascible and clever barrister played by Leo McKern. Mortimer also adapted Evelyn Waugh’s “Brideshead Revisited” for television.

“In his introduction to ‘The Oxford Book of Humor,’ Peter Shaffer says that humor is a silly way to attack human ills. But that’s nonsense. Look at Dickens. In fact, the best way to attack anything is to get it laughed at. The thing about trying to resist the developers is that everyone has such feelings of impotence. We had a meeting to protest the redevelopment near us and it was like Tian An Men Square, but we did defeat the building of the new town.”

The struggle inspired “Titmuss Regained,” a sequel to Mortimer’s “Paradise Postponed,” a novel about the rise of a thoroughly nasty young Tory politician.

One of those who also fought against the new town was Michael Heseltine, a Conservative member of Parliament who would be the likely successor to Margaret Thatcher as prime minister.

“I congratulated Michael on his good work in the fight and he said, ‘Thank you but please don’t say so in public or you’ll ruin me.’ I told him if he kept up the good work I’d write an article attacking him savagely. He said, ‘Oh, thank you.’ ”

Mortimer’s father was a barrister, who went blind during the last years of his life. Mortimer wrote a radio play about him called “Voyage Round My Father.” It became a stage play, with Alec Guinness in the role and then a television drama starring Laurence Olivier.

“I live in my father’s house and sleep in his bed,” Mortimer says. “We filmed the television version at the house, and I watched Olivier as my father die in the bed in which I watched my father die. It was a strange metaphor for the writer’s life.

“Graham Greene said writing makes your eyes so tired--having to watch your characters all the time. It’s particularly true when you’re writing for television or the stage. You have to see what your characters are doing all the time.”

The greatly popular Horace Rumpole is modeled in considerable part on Mortimer’s father. “My father was forever quoting poetry, as Rumpole does, and he dressed as Rumpole does--a cape, and with cigar ashes all down his front.”

The Rumpole stories are collected in two fat omnibus volumes, and while one is called “Rumpole’s Last Case,” the title was ironic. Rumpole had put 100 pounds on a four-horse parlay or accumulator, and the winnings would have let him retire to a tropical island. But the bookie retired with the winnings, leaving Rumpole to go harrumphing on beneath his wig. Six more Rumpoles have been done and will be along, and there will almost certainly be more. “Leo (McKern) worries about being identified solely with the part,” Mortimer said. But it is probably too late to worry; by now McKern has the kind of irreversible linkage Basil Rathbone had with Sherlock Holmes.

Rumpole is a character Mortimer loves and loves to write about. “You think of Chandler’s hero walking down those mean streets. I think of Rumpole operating in those mean courts. Rumpole can say all the things I feel. Qt’s just that if I said them, they’d be dismissed as trendy and left-wing.”

Mortimer followed his father’s footsteps and became a barrister, specializing initially, also like his father, in divorce cases. But he wearied of the practice and gravitated toward civil liberty and censorship cases. He had been writing all the time, inspired by a wartime stint with a documentary film unit. He found, as he has said, that he could develop no authority as an assistant director and was urged to try the typewriter.

A short story became a Peter Sellers film called “The Dock Brief.” That led to other scripts, including “Bunny Lake Is Missing” for Otto Preminger and “John and Mary,” which starred Dustin Hoffman and Mia Farrow. Several others went unmade (“You can have a very nice life writing scripts that never get produced.”)

Energetic and prolific, he also wrote several novels, then abandoned the form for several years to concentrate on scripts and plays. (The abandonment was partly because his then-wife, Penelope Mortimer, was also writing novels, “The Pumpkin Eater” most notably, and one novelist per household seemed a reasonable quota.)

He returned to the form with “Paradise Regained,” his well-observed portrait of a pol on the make in the Thatcher era. “You do everything in dialogue, and then you discover again the wonderful freedom the novelist has--to go inside his characters, to roam around past, present and future.

Two years ago, Mortimer wrote another novel, “Summer’s Lease,” a satirically comic mystery, rising toward tragedy, about an English family taking a villa in Siena for their summer holiday and growing curious about their absentee landlord and the notes he has left them.

“Summer’s Lease” has also been filmed for television by Thames and will be along here, probably in 1991. John Gielgud will play the wife-heroine’s hard-drinking and disreputable father, a columnist.

“When I wrote the novel, I said, ‘This will never do for television; it’s too interior.’ ” But by the judicious use of voice-overs and some expanded father-daughter conversations, Mortimer thinks he has made it work.

He insists on adapting his own work. “I couldn’t let anybody else write Rumpole’s dialogue, or Titmuss’s.” He also has a say-so on casting and the pleasure of seeing not a word changed without his permission.

Mortimer has left his law practice for full-time writing and says he doesn’t miss the law. “As you get on, the stakes in the cases you’re arguing are higher and higher. If you write a bad book, it doesn’t matter; you simply write another one. But if you ask the wrong question in court, you can put your client in prison for quite a stretch of time.”

But the law was helpful in many ways. “Telling a story so 12 good jurors and true can follow it is very useful training.” The secret of Rumpole’s success, Mortimer has no doubt, is that he is a deflater of pomposity, a defier of authority and a figure no less romantic for being so untidy.

And he does have a following. In San Francisco, Mortimer was guest of honor at a dinner of the Rumpole Society, where he discovered there are “She Who Must Be Obeyed” T-shirts (acknowledging Rumpole’s phrase for his put-upon wife) and a member who has “RUMPOLE” license plates.