Eileen Atkins hates to fly, but there's one mile-high trip she's glad she braved. The veteran British actress visited Los Angeles in 2008 to promote her role in the miniseries "Cranford," which would lead to an Emmy win. On the all-night flight back to London, publicists paired her with "Cranford" writer Heidi Thomas so that "we couldn't bore anybody else to death," she said.

It was during that journey that Thomas suggested a return to a much-heralded series that Atkins co-created 40 years ago with gal pal Jean Marsh, riveting audiences on both sides of the pond.

"Upstairs Downstairs," which lasted five seasons and netted three Emmys for best drama, was an unlikely smash, managing to depict both English aristocrats and their servants as three-dimensional characters.

Few gave it much of a chance. It was considered a vanity project for the two actresses. Marsh went on to play Rose, the ever-reliable maid, but Atkins had to bow out of her role as Rose's flamboyant roommate because she was playing Queen Victoria on stage when the series finally got a green light. British executives were so underwhelmed by the pilot episode that the master tapes collected dust for almost a year before airing. Even then, the show seemed cursed by scant promotion and a technicians' strike that caused early episodes to be broadcast in black-and-white.

When London Weekend Television shopped it stateside, PBS' "Masterpiece Theatre," which was just getting started, passed before finally relenting.

"It wasn't an adaptation of a classic," said "Masterpiece" producer Rebecca Eaton. "It was considered a soap opera, just lowbrow television."

But "Upstairs" was anything but lowbrow, and viewers immediately understood they were witnessing some of the most daring drama on the air. I recently went back and devoured the first 20 episodes, which -- though set in the early 20th century -- took on such topics as public nudity, homosexuality, mental illness, suicide, rape, murder, May-December romances and prison abuse.

Pretty heady stuff for the early 1970s -- or not. It's no coincidence that "All in the Family," in which an unapologetic bigot presided from his easy chair, and "M*A*S*H", an anti-Vietnam War sitcom disguised as an anti-Korean War sitcom, both were launched around the same time.

But networks and public television were more squeamish in the ensuing decades, which may explain why a sequel hasn't arrived earlier, although Atkins and Marsh almost did something darned close about a decade ago.

Robert Altman was working on "Gosford Park," another "class" drama wrapped around a murder mystery, and tried to recruit acclaimed playwright Tom Stoppard (whose son, Ed, has a key role in the new "Upstairs"). Stoppard declined, but recommended Atkins and Marsh.

"Robert Altman would say, 'Come and talk to me in Texas,' but we were very tentative and nervous about it and we were both busy," Atkins said. "We did a treatment and he didn't like it, which was fair dues. We hadn't really wanted to do it." Atkins did nab a role in the film, eventually penned by Oscar winner Julian Fellowes, finally getting her chance to play a "downstairs" servant.

Atkins also pops up in the new production, promoting herself to the near-regal family that has just moved into 165 Eaton Place in 1936. The three hours, which air on Sunday evenings starting this weekend, set the stage for World War II, with talk of fascism on both floors and out on the streets. The only familiar face from the original series is Marsh as Rose, but the audacity remains as both classes must confront pride and prejudice. British audiences have already responded with great enthusiasm. The airing this past December drew 8.5 million viewers, a blockbuster number in England.

Despite Thomas' solid script and some terrific performances from two grande ol' dames, you may find yourself wistful for the original production. Good news: Acorn Media unveiled a new box set late last month that includes all five seasons and 25 hours of bonus material. With luck, you'll appreciate the work more than at least one original cast member did.

According to Marsh, Rachel Gurney, who played Lady Marjorie Bellamy in the first season, came into some money and asked to be written out of the show. At the start of the second season, her character drowned on the Titanic.

"At some point, either she ran though the money or she got bored and she wanted to come back," Marsh said. "She went to [producer] John Hawkesworth and said, 'Could you please write me back in, darling?' And he said, 'Rachel, the only person who could write you back in is Jacques Cousteau.'"