It was inevitably being described as a "double whammy" for the House. The casting had filled opera-lovers with delicious anticipation. In Strauss's opera, the eponymous Arabella, daughter of a dissolute count, and the dashing Croatian landlord Mandryka, who falls in love with her, are both young parts; the emotions that wrack them are callow, barely post-pubescent. But Strauss's score is of such difficulty that the roles are normally tackled by singers well into middle age. In Terfel and Roocroft, the ROH had succeeded in capturing two singers with soaring reputations and voices big enough for the challenge, who were also just about young enough - they are both 30 - to sing the Mills-and-Boon-ish libretto with a degree of plausibility. It was also going to be the first time they had sung together, a "dream-team debut".
Now Covent Garden has lost them both. And it comes in the wake of the painfully public let-downs the House had to put up with during the documentary series: Denyce Graves pulling out of Carmen after one performance with a sore throat, and Jeffrey Black in Figaro having to be replaced at the last minute by a singer, Thomas Allen, who had never even clapped eyes on the set or conductor before he went on stage. To the outsider it looks like carelessness or worse - a bad habit. The House keeps on giving these youngsters their big breaks; for its pains, it keeps getting its face slapped. Most astonishingly of all to the non-opera- going lay person, there seems to be no comeback, no showdowns in court. The House smiles sweetly and turns the other cheek. "They've been absolutely wonderful about it," trilled Doreen O'Neill, Terfel's agent, yesterday.
Why can opera singers get away with the sort of apparent caprice that in other industries, in today's grim business climate, would lead without much delay to termination of the relationship?
The essential reason is because in most cases it is not caprice.. Pavarotti is notorious for cancelling performances at short notice but nobody has given him his cards. Correction - Ardis Krainik, director of the Chicago Lyric Opera, did just that in 1989, sacking him publicly and in perpetuity for reneging on 24 out of 41 scheduled performances. But that was one particularly iron-willed American. There are few others in the opera world with that sort of style.
Terfel has gone down so sensationally in America that he has been lumbered with the awful nickname "Taffyrotti". But he has yet to develop an ego to match the nickname, and neither he nor Roocroft has a reputation for leaving opera houses in the lurch. Terfel's work schedule, however, helps to explain why opera fans around the world are increasingly being disappointed by their favourite stars.
Terfel made his debut at the Salzburg Festival in 1992, and, after singing at New York's Metropolitan Opera House two years later, his career took off like a rocket - he is now booked solid through 1999 and his agent is taking reservations for well into the next century.
It is natural that the world's opera houses should want to get their claws into the up-and-coming stars good and early; but it is equally natural, nay inevitable, that Bryn Terfel cannot besure what his circumstances will be two, three, four or seven years hence. Terfel is currently singing the role of Nick Shadow in Stravinsky's The Rake's Progress with the Welsh National Opera. His agent explains that "He didn't realise until he sang it on stage what a demanding role it was going to be. He's learnt all the part of Mansryka [in Arabella], but he felt that he wouldn't do full justice to it, and as he's a perfectionist, rather than give it 90 per cent, he decided to withdraw."
Amanda Roocroft's excuse is even better. Two years ago, when she signed up for Arabella, she couldn't have known that four months before it was to open she was going to have a baby; nor that, following the birth, she would have such a struggle to rebuild her strength. "It's not because she wanted to be indulged as a new mother," the press office at Covent Garden insists, "but she needs more time to build up her stamina."
The scathing reviews that followed her Wigmore Hall recital last month (after she had already announced that she was pulling out of Arabella) will have convinced her she made the right decision.
Covent Garden, like other opera houses in similar situations, is left to scrabble around for last-minute substitutes, paying top dollar for names (such as the American soprano Cheryl Studer, who replaces Roocroft) that will keep the box office busy. But the Royal Opera is not too desperately in need of our sympathy. For all the moaning about unfairness that preceded the showing of The House, the documentary series has done Covent Garden enormous good in terms of public interest; requests to join the mailing list have poured in, and ticket sales are up.
Whatever the backstage controversies the programme exposed, it also revealed the true glamour and excitement of an opera house's work, which has nothing to do with tedious arguments about elitism.
Now the dramatic comings and goings of famous principals help to keep that memory fresh. And when the action on stage is as clunky and contrived as that provided by Strauss's Arabella, a few off-stage frissons can only help to keep the place alive.