This autumn is Strauss and Freud season in London: while the Royal Opera are showing Charles Edwards’s searingly Freudian take on Richard Strauss’s Elektra, ENO have opted for the polar opposite mood with Johann Strauss’s Die Fledermaus: Christopher Alden’s production is just as Viennese, just as laden with dreams and sexuality, but filled to the brim with gags and frivolous decadence.

If you are going to this with any set ideas about what modern opera “concept productions” are like (or, indeed, what operetta is like), leave your preconceptions at the cloakroom on the way in: this is the kind of production that could give both Regietheater and operetta a good name.

The outer wrapping of Allen Moyer’s sets are plain enough, notably overshadowed by a giant fob watch which swings like a hypnotist’s pendulum in nearly continuous motion. Costume designer Constance Hoffman clothes the principals in fin-de-siècle elegance (except for Alfred the tenor, clad in full Elizabethan doublet and hose) and the chorus in a riot of burlesque weirdness: giant cracks open up in bedroom walls to usher in Rosalinde and Eisenstein’s desires made flesh; the staircase and costumes in Prince Orlov’s evoke Busby Berkeley musicals; the prison coach is pulled by men in nightmare crow’s head masks. The title Die Fledermaus (“The bat”) is the cue for a general vampire feel to be added into the mix, with video projections of bats swirling round and a truly splendid pair of giant bat wings and Dracula cape for Richard Burkhard’s Dr Falke.

The plot of Die Fledermaus defies synopsis, so I’m not going to try: suffice to say that it’s very much in the bedroom farce genre and thoroughly entertaining. Stephen Lawless’s translation adds enormously to the fun. I don’t know the original German all that well, but I think it’s a safe bet that some serious liberties were taken and that much of the dialogue was new; amongst the many gags, look out for the hilarious episode when the convicted Eisenstein and the prison governor Frank are both masquerading as Frenchmen – without, of course, knowing a word of French between them. There are excellent, inventive, riotously funny acting performances from the whole cast: combine this with visuals that are constantly both stylish and slightly disturbing, wrap it around Strauss’s heady, devil-may-care music – which sounds deliciously nostalgic to modern ears – and you get a powerful brew. As the opera draws towards a close, Alden throws in the point that what we’re seeing are the happy days of empire drawing to a close, soon to be smashed on the iron fist of Nazism. Some neat lighting tricks and a brilliant piece of acting by Jan Pohl as the jailer Frosch turn this into some powerful imagery. Gaiety and frivolity may have abounded, but you are suddenly made to stop and think.

Musically, things are uneven. Young Korean conductor Eun Sun Kim didn’t do much wrong, but nor did she add a truly great level of Viennese sparkle. The style of Strauss’s music is very familiar, the tunes are familiar, and it needs an extra something to lift it out of the ordinary – be it lilt, dynamics or a particularly well turned phrase. That extra something was missing, and by the end of the second act, the bubbles began to be just a touch flat. In particular, Rosalinde’s big number, the Act II czardas, never really achieved lift-off, which marred an otherwise thoroughly decent performance from Julia Sporsén.

Die Fledermaus has a big cast, and the quality was high throughout. The pick of the singers was Rhian Lois in the soubrette role of the maid Adele, who truly threw her voice at the role, producing energy and excitement at every turn. Edgaras Montvidas entertained thoroughly as the tenor Alfred, singing a caricature of himself with panache. Tom Randle made a great hapless fool as Eisenstein, Richard Burkhard clearly relished the evil genius role of Falke, and Jennifer Holloway produced marvels of Russian-accented speech even if her singing was somewhat underpowered.

Die Fledermaus is an operetta written in another century when attitudes were very different from today, and it’s a difficult task to turn it into something that is fresh and vibrant today, exciting the senses and making us laugh and think. I may quibble about details, but overall, this production accomplishes that task with flying colours, makes a great case for directors throwing new concepts into old operas, and makes for a great operatic night out.