In a country that cherishes ceremony and at a club that reveres tradition--where heated rows have developed over the acceptability of blue trim on white outfits--Commander Charles Douglas Lane has become a Wimbledon legend. He is one of a handful of notables tapped by the All England Lawn Tennis and Croquet Club's exclusive membership of 375 as an honorary member for his "distinguished service to the game of tennis."

The Commander, as he is called, marches briskly into the small, cluttered locker room, at 81 a dignified, imposing British gentleman who, if life were a movie, would be played by Sir Alec Guinness. He wears a uniform of regulation tennis whites--long pants, sport shirt and V-neck sweater--a pair of small gold spectacles and an air of strict propriety.

He is in charge of a hand-picked army of 70 boys and 14 girls, chosen from hundreds of hopefuls to serve as ball boys and ball girls at the world's most celebrated tennis tournament--the annual championships at Wimbledon--which begins here today.

Before him now are 14 youngsters who grow respectfully silent as the six-foot-tall retired naval officer makes a few strategic marks on a diagram tacked to the wall. These youngsters are the fastest and finest of the chosen, their scrubbed and serious faces reflecting both pride and nervousness. This is first-court team practice, and the elite cadre leans forward on low benches awaiting Lane's instruction.

For three weeks he has drilled the entire group, in clusters of about a dozen, in the subtleties of their art--which includes placing the foot perpendicular to the base line so the balls roll straight, keeping heels together at a 45-degree angle when stopping a ball, darting across the court to capture stray balls at a swift, even speed. During this initial training he has made detailed notes on each youngster's progress, and organized them into teams according to ability. Each team is assigned to a specific court for the duration of the event Lane calls simply "the fortnight."

Now, with the first-court team, the Commander launches into an address that, in bygone days, he might have used to prepare troops for battle. Today, with minor changes, the speech serves to inspire the boys chosen for the most prestigious assignments--Centre Court and Court 1.

"Brains on, please," he says, his own obviously humming in high gear beneath a fringe of salt-colored hair. "You have ever so much more to learn and much of it is quite complicated . . . The ball changes, the tie-break, the guard of honor.

"When you have 15,000 people looking at you, plus all sorts of thousands more watching you on the television, your adrenal glands will start pumping hormones into your bloodstream. So it is absolutely essential that you exert every effort to remain in complete control.

"But do not look on any of this extra work as beyond your scope, because it is not. Make your body believe that you are going to succeed, and you will succeed. With the eyes of the world upon you, you will change the balls with perfect precision and announce clearly to the chair umpire, 'Sir, the balls have been changed.' A moment of triumph! So no matter how difficult a task may seem now, whatever you do, don't lose heart."

During their six weeks with Lane, awe seems to be the youngsters' predominant emotion toward him. Each one receives several pages of rules and instructions to memorize--the most crucial of which is called "The Ball Boy's Bible."

It begins with the warning--underlined, in capital letters--that "AN ERROR BY A BALL GIRL-BOY COULD COST A PLAYER STERLING POUNDS." Next come Lane's five commandments:

1. Concentration.

2. Scoring and knowledge of the game.

3. To keep still.

4. To be fleet of foot.

5. A placid temperament under all conditions.

Smoking, combs, jewelry or "talking to unknown girls-boys" on court are strictly forbidden.

Absence is unexcused "unless you are dead, dying or about to die."

Boys must shave daily (if necessary), and girls may have their hair done by the club's beauticians.

"Being a ball boy at Wimbledon makes you a part of history," says Jon Cummings, a square-jawed, blue-eyed 16-year-old who likes funk music and plans to leave school soon to find a job, preferably in a recording studio. "We get to meet royalty. It's an achievement that, when you get married, you can tell your kids about."

The Commander's crew of ball boys and girls shares in the glory of one of tennis' premier events. For their crackerjack performance in handling the 1,200 dozen balls used in each championship, the youngsters get fan mail, gifts and congratulatory calls from around the world. Although they receive no pay--just expenses, a certificate and their uniform--it is a high honor that makes them, says Centre Court team captain Paul Samme, "the envy of all our mates.

"When the headmaster phoned up to tell me I was captain of the Centre Court team, me mum burst into tears," says the earnest sandy-haired 16-year-old, who is fond of sociology and rugby. "She started notifying all the relatives in Canada."

Like Samme, all the ball boys and ball girls are students in the London borough of Merton, the closest school system to Wimbledon. Originally (starting with the first championship in 1877) orphans from a London boys' home did the job. In 1966, the school where Lane served as bursar (after retiring from the navy) was asked to supply the boys. Three years later, when that school's headmaster decided he couldn't supply as many boys as required, the state school system took over. Lane, a former tennis umpire and longtime player known for his extraordinary spinning underhand serve, stayed on as trainer.

For most of this middle- and working-class group--many of whom will leave school for the work force or, in this country with high unemployment, possibly the dole at age 16--ball-boying is a once-in-a-lifetime shot at glory. They devote themselves to the task and to the Commander with fierce dedication. Some dream of making their own Wimbledon history, like the ball boy who caught a loose ball with a midair somersault on the run and won a standing ovation from the crowd.

Ball-boying is also "a great way to meet some real fit ones," says Robert Elkington, 15, using his school's slang for "nicely shaped girls." Like groupies drawn to rock stars, gaggles of schoolgirls gather by the ball boys' locker room or send letters--with photos enclosed--addressed to the Cute Blond Ball Boy at Right Base on Court 3.

"One of me mates got 11 phone numbers on the first day," boasts Elkington, who will be on Centre Court. "And he was only on an outside court."

The major misconception about ball boys and ball girls is that "they just come down here and walk on the court," says Wally Wonfor, director of outdoor pursuits and sports for Merton's schools, who selects the youngsters. "Most of these kids don't know the first thing about tennis when we get them. Spectators who see the finished article have no idea of all the work that is involved."

The process begins in January when Wonfor sends letters to 14 area high schools, soliciting applicants aged 15 to 17. Physical-education teachers weed out the unsuitables, leaving about 125 boys and 45 girls to try out--"separately, of course"--for the 70 boys' spots and 14 girls' spots.

"In March, for about three weeks, I put them in a gym and literally knock hell out of them," says Wonfor, 53, who plays tough drill sergeant to Lane's genteel commander.

The main quality Wonfor looks for is temperament. "Tennis players are playing for a heck of a lot of money, and the least little thing can upset them," he says. "The ball boys are the nearest thing for the players to vent their feeling on. One time a player, who shall remain nameless, threw his racket at a ball boy and just missed him. The ball boy picked up the racket, held it by the head, draped it over his other arm and handed it back to the player with a smile. That's the ticket. The crowd loved it."

To impress on the youngsters the need to "smile no matter what," Wonfor requires them to "smile through the whole three weeks. If I find them without humor on their face I make them do 10 push-ups. And while they're doing the push-ups I stand over them to make sure they keep smiling."

Speed, stamina and coordination are also important. "I put a pedometer on a kid at the net one day," Wonfor says. "He ran three miles in one match, and those kids can do anything up to five matches in one day."

The girls, says Wonfor, "get exactly the same treatment as the boys. I figure that if I can't make them cry, McEnroe can't make them cry." Wimbledon first permitted ball girls on court in 1977, but they are relegated to "the sticks" of courts 10, 11 and 12.

While some day there may be a more even ratio of boys to girls, he says, "I don't think you'll ever see ball girls on Centre Court. You may have noticed that when you walk through the gates of Wimbledon you go back 50 years."

The 14 top ball boys say they'd like to see John McEnroe and Jimmy Connors in the final because "they're the best" and they offer these opinions about other players: Vitas Gerulaitis "thinks he's the coolest bloke out, like a high-class playboy or something, throwing his racket around and making you pick up his towels."

Ilie Nastase: "A comic. He's fun, but it would be hard to be on his court because he's always mucking about, and that would distract you."

Chris Evert Lloyd: "She's all right. Nice figure."

Sue Barker: "The best British player we've got."

Virginia Wade: "Rather a b---- on court."

Jimmy Connors: "He's a poser. He's always playing to the crowd's sympathy."

John McEnroe: "He's hated by most people, but they still want to come and see him play."

The players also express opinions about the ball boys and girls, says Wonfor, who "rides herd" on the youngsters throughout the training and during the championship. "Billie Jean King always brings a huge bag of toffees down to the kids with a letter thanking them for their help," he says. "Evonne Goolagong Cawley always pokes her head in and says thanks. So do Stan Smith and Chrissy Lloyd."

There is, Lane admits, "an enormous amount to learn and retain." Some of it is a matter of form, such as proper posture to ensure that the balls will be rolled straight. Some is a matter of function, like keeping proper count of the games played so the balls are changed at the correct interval. And some rules are simply a question of style.

"Do not let the ball pass through your legs," the Commander tells the boys. "It looks ghastly. And far worse is the doglike movement of cocking the leg up to let the ball roll by. I won't have it. Although the temptation is great, I ask you to step aside to let the ball roll by."

In addition to criticism--"keep still, Brown, third commandment" or "don't you dare touch the net, Master Fossett"--Lane also praises good performance, generally with a simple, treasured "well done."

And at the end of the practice he tells the group they are "the best I've had in years. Most exhilarating."

Although the boys are excited about this year's championship, they are also anxious not to "bodge up."

"I have this nightmare that my mind goes blank," admits Alphanso Francis, 16. "If that happens with all those people watching, I don't think I can cope with it."

"I just don't want to fall over," says Barry Gartell, who at 13 got special permission from his headmaster to be a ball boy. "My brother was a ball boy last year, and he got hit in the head by a ball. It raised a bump. He told me to crouch down and to concentrate."

Gartell says he'd "rather not be on a court with McEnroe or anyone who shouts at you."

The ball boys and girls--who train on separate days--arrive at Wimbledon a half-hour before each training session to take tea in the clubhouse. Afterward they adjourn to the courts for 2 1/2 hours of instruction and drills, during which two Wimbledon members play a match while the youngsters practice their parts and the Commander coaches from the sidelines.

"No, no, no, Smith," Lane bellowed from the base line during a recent session with the top two teams of boys. "Never, never stop a ball with the bottom of your foot. I've seen a server refuse to accept a ball that had been slightly squashed like that by a boy's foot. You must always stop the ball exactly as you do in cricket, with your heels together and your hands in front."

To a boy who pauses slightly before tossing the server a ball, Lane warns, "Most players, Bailey, don't mind waiting. But if you get McEnroe or someone like that . . ." He shuts his eyes and shakes his head sadly at the grim consequences.

"Arthur Ashe says that they are the best in the world," Lane sums up later. "And they are, too, by what I've seen. They have discipline, concentration and a love of their work. They take infinite trouble with the little nitty-gritty things. And that, you see, is the whole point."