When Handel wrote Semele in 1744, he seemed unsure about its nature describing it as "a musical drama ... after the manner of an oratorio." In other words, it was a sort of opera, but without costumes and scenery and with restricted acting. That description was partly dictated by the English establishment's ban on operas in London during Lent, so instead of operas in Italian, Handel composed English oratorios.

Semele represented a vital shift in his transition to operas in English but was shunned by many as it did not meet their expectations. The opera-lovers disliked it because it was not an Italian opera, while the oratorio lovers disapproved of its irreligious plot.

Even now, the Royal Opera House felt obliged to offer guidance about Semele, warning that the plot contained "depictions of violence, murder and traumatic childbirth", though most modern opera-goers are quite used to such things. The story comes from Greco-Roman myth and concerns an affair between the God Jupiter and his servant Semele, much to the disapproval of Jupiter's wife Juno. (Interestingly, the Royal Opera did not feel that it had to warn us about adultery.)

Jupiter had adopted human form for this relationship and Semele's big mistake was to make him promise to reveal himself in all his Godly glory. Jupiter knew this would kill her, but a promise is a promise, so Semele was frazzled to a crisp, nut not before she had become the only mortal to give birth to a God, Bacchus the god of wine and fertility.

Oliver Mears, the Royal Opera's Director of Music, set this production in modern times, with Jupiter's home rather ordinary by godly standards. To accentuate the modernity, the costumes are depressingly ordinary, with Jupiter in a suit, and several characters relax by lighting up a cigarette.

As Mears says in the programme, "There's always something interesting about reflecting the world around us," but such pursuit of relevance so often adds drabness. The Greeks and Romans understood it well, making their gods all-powerful but also full of human weaknesses, such as violence, arrogance and lust, which makes them all too easy to both worship and identify with. Our modern gods tend to view morality rather differently.

Perhaps Handel's audiences knew their Greek and Roman myths better than we do today, but the first two acts are not easy to follow if you do not know the characters. With the gods looking ordinary, it took even more getting used to and it was not until the third act that the story became absorbing. Until then, we could just settle comfortably in our seats and enjoy some of Handel's most glorious music, performed magnificently by an exceptional cast. The soprano Pretty Yende was glorious in the title role, her beautiful voice surmounting all the challenges of Handel's demanding, often fast music and portraying the full range of emotions demanded by the part.

Her delivery of the aria "Myself I shall adore" displayed impressive passion to begin with the vanity suggested by the lyrics, then changing to anger at Juno's deception that would lead to her death. She was an excellent match for mezzo-soprano Alice Coote, who played Juno, who was deliciously scheming throughout, determined to get her way with Jupiter without directing confronting him.

The tenor Ben Bliss looked very ordinary for Jupiter, leader of the Gods, but his voice was sublime. His delivery of the opera's best known aria, Where'er you walk, was supremely elegant and surprisingly effective for such a well-known piece.

With strong performances from Irish mezzo-soprano Niamh O'Sullivan as Semele's sister Ino and Armenian soprano Marianna Hovanisyan as Juno's assistant Iris, the cast cannot be faulted, but the performance that gave much-needed cheer was that of British bass Brindley Sherratt as Somnus, God of Sleep. His reluctance to rise from a slimy bathtub in order to aid Juno's schemes provided much-needed humour to an otherwise bleak production.