Of the various themes that make up Britten’s Gloriana, written to celebrate the coronation in 1953 and being given a rare outing at Covent Garden to mark the work’s 60th anniversary and Britten’s 100th, the most effective by far is a sort of operatic expansion of Shakespeare’s line “uneasy lies the head that wears the crown”.

Britten aims a harsh spotlight at two faces of Queen Elizabeth I and stares at them with a steely, unblinking eye. On the one hand, the Gloriana of the title role, an intelligent stateswoman who knows who to trust and who to be wary of, and an adept politician brilliant at working a crowd. On the other, an ageing woman increasingly worn down by the cares of state, still desperately in love with her “Robin” (Robert Devereux, the Earl of Essex) but being torn from him.

One can only wonder what was going through Britten’s mind when he composed the opera to celebrate the accession of a new, young Queen Elizabeth, full of hope for what has turned out to be a long and respected reign. The Queen was diligent in studying the opera beforehand and polite in her response (the experience does not seem to have engendered an enduring love of opera); for most of the invited first night audience, Gloriana predictably went down like a lead balloon.

But viewed in the absence of any celebratory royalist glasses, the scenes between Elizabeth and Essex are riveting, especially when performed as well as they were by Susan Bullock and Toby Spence. Especially intense was the moment in Act III when Essex, fresh from defeat in Ireland, bursts into Elizabeth’s chamber, finding her “an aged woman unadorned”. There’s an explosion of conflicting emotions: Spence shocked, pleading, ardent; Bullock imperious, nostalgic, angry. The reprise of their nostalgic duet “happy we were” was bittersweet, melodic and compelling. This was brilliant theatre, brilliantly performed. Another superb scene is a dramatic moment at court revolving round Lady Essex’s dress – a coup de théâtre that I won’t spoil for you.

But sadly, Gloriana contains an awful lot of material that falls a long way short of that standard. The interplay at court doesn’t give much scope for character development of anyone except Elizabeth and Essex. The Royal Opera assembled some great singers (Patricia Bardon as Lady Essex, Kate Royal as his sister, Mark Stone as her lover Mountjoy, Clive Bayley as Raleigh) and all sang to a high standard and acted decently, but the opera doesn’t really give them scope to shine individually.

Gloriana also contains a great deal of celebratory padding, much of it written in a sort of English pastoral style. It’s not my favourite style of music at the best of times, and I found a great deal of it fearfully dull. The Masque in Act II Scene I, where the Queen is entertained at Norwich, contains some of the most famous music in the opera, the Tudor pastiche “courtly dances”, but I found the scene interminable (as, ironically, Essex predicts in the libretto).

Britten’s music bursts with invention – which is a mixed blessing. There are so many different themes and styles, all performed with excellence by the Royal Opera orchestra under Paul Daniel, that there are many moments to savour, but it’s difficult to gain any sense of progression. The score is at its best when Britten is subtly insinuating Tudor themes into his modernist style.

Richard Jones’ staging does its best. There’s a visual framing story of Queen Elizabeth II attending pageants in her honour, with plenty of 1950s civic kitsch and schoolchildren clad in grey Clydella holding up cards to tell us where the action is. For the main action, we get a primary-school history book version of Elizabethan costumes, with bold designs and primary colours (credited, somewhat enigmatically, to “Ultz”), and blocky, geometric sets. It’s a great production visually.

But the best efforts of a fine performance and production can’t lift this piece to the level of Britten’s operatic masterpieces. It simply lacks the sustained drama of Peter Grimes or Billy Budd, or the slow-burn psychology of Death in Venice. Ultimately, this is a four-star performance of a two-star opera.