"But," says Jewitt, "people's expectations may not be quite met by what we find to be authentic." In other words, Eliza Doolittle and Henry Higgins would not have sounded as we imagine them in Pygmalion -- and certainly not as they did in the Hollywood film My Fair Lady.Andrew Wade, head of voice at the Royal Shakespeare Company, supports research to find appropriate accents for a particular piece, but warns that, among young actors, accents are a delicate matter. As, indeed, they are for everyone.Actors of Prunella Scales's generation tend to sound like Laurence Olivier and Joan Plowright, even when they were brought up in one room in Bermondsey. The training process stripped them of all audible signs of class and regional origin. Now the pendulum has swung again, and nobody is proud to speak posh. Instead they want to declaim their origins as much as does the blank verse of the Bard. Actors, says Ward, want to "come from their root sound": to take their own natural accent, be it Geordie or Brum, as their starting point. And the RSC accommodates them: Shakespeare no longer has to speak Received Pronunciation (RP) - and hardly anyone else wants to do so either.RP is the educated English accent, of which "posh" is only one variant.

It may well be on the wane after 400 years of cultural dominance. First identified by name in 1869, RP was standardised in the public schools in the 19th century. But it had begun in the 16th century, as a court- based variant on the London speech of the day.Modern linguists have noted different strains. The upper class voice, still used by older members of the royal family, is called "U-RP", the U presumably coming from the U and Non-U craze of the 1950s. It has a curious kinship with Cockney: both prefer "buggah orf!" to `bugger off!'.The posh accent won't die out completely as long as Television's Two Fat Ladies command an audience. It continues to echo round the doggy halls and flagstoned kitchens of the nation's country "hices".

It shrieks in the editorial offices of some of our leading magazines. Sometimes it is turned on the unfortunate shop assistants of Cheltenham.But its institutional presence is reduced The speaking clock is no longer a schoolmarm. The disembodied voice on the London Underground now says "Mind the gap" rather than "Mend the gep".Auntie BBC spoke RP as late as the 1960s, especially on its children's programmes. But most RP speakers have adopted a compromise form called "mainstream" or "modified" RP, and it is that which the BBC reserves for news and funerals. Elsewhere, of course, it sounds like everything from a stroppy teenager to a football hooligan to a kind health visitor wondering whether you'd like your food cut up.Traditional RP is spoken by only some 3 per cent of the population: it is much more popular with the 1.5 billion speakers of English abroad - which is why the "best" English is sometimes said to be spoken in Calcutta.