Some operas feel the pinch worse than others. Opera Holland Park’s austere wartime Hansel and Gretel is decent enough in the end but could do with the sort of magical touches only big bucks provide.

Stephen Barlow’s production owes more to CS Lewis than the Brothers Grimm. The titular siblings are a pair of well-contrasted wartime schoolkids. Joana Seara’s Gretel is all sugar and spice, and there’s more than a whiff of puppy dog’s tail about Catherine Hopper’s Hansel.

The set is conceptual and monochrome: a lovely sylvan print, and a massive door that’s an entrance to the kids’ home, the woods, everything. Engelbert Humperdinck’s opera is an inconsistent confection.

The second act (gingerbread house, the witch) is scrummy but the first act (arguments with mother, purposeless wanderings in the woods) is all exposition — a slow laying out of ingredients that relies on humour and supernatural gimmicks to stay alive.

So the gimmicks need to hit home, and here trick after trick underwhelms. The monochrome background persists. We get a Tommy Sandman and Red Cross Dew Fairy, magical beings who visit the children while lost in the woods — consistent with the concept but far from enchanting.

The magical pageant at the first half’s close is a parade of comedy penguins and low-budget angels, provided by well-drilled schoolchildren. Mr Cowell has made it clear that for kiddy kitsch the gloves are off, so here it is: it looked sweet, but not wondrous.

It was saved though, by Peter Selwyn’s reduced orchestra, which really shines in the interludes. The children’s goodnight hymn was likewise beautifully handled, tuned to Seara’s rather quiet lead line.

A shame Selwyn’s comic timing isn’t so strong — it’s a real hindrance in the endless scenes with the kids at play, which must come out funny or annoying.

Colour comes to the production in the second half with Anne Mason’s lime-green vision of a witch. A fluorescent Miss Hannigan, she’s the shot in the arm we need. From her entrance onwards, all is fine. At her death, a D-Day street party brings Barlow’s conceit to a joyous conclusion.

From dark times, we have emerged secure. It’s a lovely feeling ­ but the dark times were drab, and that’s not a balance peacetime audiences need tolerate.

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