Throughout its two-month tour of Britain, English Touring Opera's production of Donizetti's opera Anna Bolena has been picking up good reviews. On Saturday, Perth found out why as the opera closed its run at the Perth Festival with a stunning performance and presentation.

There are myriad reasons why this production and performance were so deeply impressive, not least the appropriate historical costuming and setting of the tale, its darkly-lit and economical set, in which sliding panels of tapestries played a critical role, and the magical tailoring of the opera to the stage proportions of a small theatre - a virtuosic use of space.

Add into that mix the fact that the opera, with effectively seven principal characters, is difficult to cast successfully, and that ETO produced a strong, highly unified set of singers, well-seasoned and seamlessly cohesive in ensemble by the end of the run, and you can begin to explain the tremendous focus and coherence of the performance.

Add in further the glorious, 14-strong little chorus with a big sound, and the immaculately balanced playing of the small ETO orchestra, conducted with an impeccable sense of style by Michael Lloyd, and the picture becomes yet clearer.

Then consider the series of dramatic coups de theatre in the revealing exploration by director James Conway of the main relationships in the opera, principally the deeply poignant and ambiguous tension between Anne Boleyn and Richard Percy, the hair-raisingly tactile and sensuous relationship between Jane Seymour and Henry VIII and, of course, the spectacular and somehow transcendent "mad scene" of Anne at the close. It all amounted to a rather extraordinary operatic experience.