Satyagraha is English National Opera’s most successful contemporary opera production. Ever. It has – at a generous estimate – seven tunes. This is seven more than most contemporary operas, I hear you say, but when you consider that one of these persists for almost half an hour with only minor variation, and another consists purely of a rising modal scale, then this embarrassment of melodic riches looks – and sounds – less appealing.

Undisputed master of the ‘If it ain’t broke don’t fix it’ school of composition, for more than 40 years Philip Glass has been peddling his distinctive brand of minimalism. Composed in 1980, Satyagraha is the second of a triptych of ‘portrait operas’ devoted to the lives of visionary men. The focus here is Gandhi, whose history is explored through nothing so vulgar as narrative, but in a series of meditative episodes in which the philosophy of Satyagraha (whose implied meaning, if not literal translation, equates to ‘passive resistance’) is exemplified.

With a Sanskrit libretto – bleeding chunks from Hindu scriptural text the Bhagavad Gita – and no subtitles, we are deliberately kept at arm’s length from the action. Texts occasionally projected on to the stage itself offer some assistance, but only in an alienating, Brechtian way.

The direction and design of British theatre company Improbable has been widely praised for its ingenious puppetry, creating visual tableaux of great beauty and impact, but as the opera progressed and action and music remained perpetually divorced I couldn’t shake off the niggling question: to what end?

Musically, the production is exemplary. Alan Oke, returning as Gandhi, sings with sweetness of tone and conviction, and Elena Xanthoudakis as his secretary creates some glorious textural contrast with her ringing soprano. In the pit conductor Stuart Stratford is a model of precision as musical traffic warden, marshalling his orchestra and chorus through a deliberately expressionless score that’s the musical equivalent of running a marathon on a treadmill in a windowless gym.

That Satyagraha is unusual and (thought-provoking) I don’t deny. Yet something about it and the universal acclaim surrounding it makes me suspicious. It’s not that this operatic emperor has no clothes precisely, but rather that he is – at best – scantily clad in a loincloth of a couple of epigrammatic philosophies and an arpeggio or two, which can hardly be considered adequate protection against the winter chills of a recession-bound UK. For an opera about ‘deep ideas’ Satyagraha at times demonstrates an extraordinary lack of depth.

Until March 26. Box office tel: 0871 911 0200 (www.eno.org).