Barbara Hepworth at Tate Britain review – the sculptor's open-air spirit gets locked away

Behind glass ... the Boxed Hepworth room at Tate Britain stops the sculptor’s art from singing. Guy Bell/REX Shutterstock

There are so many vitrines in Tate Britain’s Barbara Hepworth exhibition that for a moment I thought I had wandered into a conceptual art exhibit by mistake. “Boxed Hepworth” – what an ironic statement about our relationship with this 20th-century British modernist, to put most of her sculptures inside transparent boxes, as if there were a glass wall of history between her and us.

I don’t know if all these see-through enclosures are there for security reasons or as some sophisticated curatorial choice, but I do know they are totally at odds with everything that sings in her art. Hepworth is a sculptor of wind and water, salt air and glancing sunlight – or rather those are the phenomena her curving, pierced, stringed carvings suggest. Her art is at one with nature. Tate Britain has locked it up in boxes in subterranean galleries that have no natural light, which does a disservice to an artist whose work deserves cool, British, ever-shifting sunlight and contemplative open space.

Not that Barbara Hepworth is one of my favourite artists. Claims for her greatness are exaggerated. If you can forget that the Romanian genius Constantin Brancusi was creating poetic forms at once abstract and natural when she was 10 years old (Hepworth was born in 1903, Brancusi had revolutionised sculpture by 1913) or that Picasso’s massive biomorphic heads show up her organicism as genteelly English – among other awkward comparisons – then sure, Hepworth was the most important sculptor of modern times. If that’s what you need to believe.

Taking on the ‘male’ art of sculpture one block of stone at a time ... Barbara Hepworth and her sculpture Single Form. Photograph: Tate

More realistically and accurately, she is a very distinctively British artist who put modernism into a particular landscape and reconnected it with history, indeed prehistory. Britain will always rightly love her for that – and, let’s not forget, for taking on the supposedly male art of sculpture at a time when women were not expected to bash at massive blocks of stone with hammer and chisel.

This exhibition’s strength is that it expertly delineates her increasingly passionate relationship with the British landscape. Hepworth’s early work is predictably international. She was a modernist in the age when modernism was called “the international style”. Carving stone and wood was a way to escape from the mechanical bronze pomp of Victorian sculpture and rediscover the raw human essence of art. Hepworth’s youthful carvings echo European primitivists from Gauguin to Henri Gaudier-Brzeska. Yet as she develops, something fascinating and – literally – earthy happens.

The belief that so-called “primitive” art is more authentic and powerful than sophisticated courtly art was a fundamental driving force of modernism in the early and mid 20th century, from Max Ernst collaging Easter Island heads to Jackson Pollock emulating Navajo sand paintings. Hepworth started to find those primal exemplars in the landscape of Britain itself. These are the islands of Stonehenge and Maeshowe after all. Hepworth starts midway through this chronological survey to carve wooden monoliths that resemble the standing stones of neolithic Britain: suddenly, her art is no longer just one more example of international modernism, but a truly personal response to the mysteries of ancient Britain.

Then she goes deeper, into the stones and caves of the very landscape. The triumphant final galleries of this exhibition reveal Hepworth at her most important and best. Her wave-like rolls and crescendos of carved wood, strung like musical intruments, have a musical power. They murmur like the sea. You can feel and dream the endless, timeless forces of nature in this truly powerful and inimitable abstract art.

There’s an old film being screened, with a narration written by the archaeologist Jaquetta Hawkes and crackly colour footage of Hepworth and her works by the sea in St Ives. But why not try to recreate at least some of the rural, sea-breezed, open-air spirit this film celebrates?

Hepworth at her best is like an invigorating walk by the sea. This exhibition does a good job of identifying the enduring strengths of her work. It all feels, however, a bit airless, as if her reputation were so fragile it must be kept behind glass, lest rough handling break it. When you work too hard to pretend a good artist is a great one, I suppose you become overprotective.

• Barbara Hepworth: Sculpture for a Modern World is at Tate Britain, London, from 24 June to 25 October 2015