A high brow strained in intense concentration is required to appreciate this uncompromising mixture of art theory and high tragedy from Howard Barker. Yet if you're willing to deepen those furrows, there's plenty of reward to be had from William Oldroyd's cool, intelligent production.

First staged in 1986, Scenes From an Execution tells of Galactia, a fictional, post-Renaissance artist in Venice commissioned by the Doge to paint a glorious, celebratory memorial of the naval Battle of Lepanto.

Committed to painting the truth as she sees it, Galactia paints a mass of mutilated flesh presided over by cruel, calculating generals, and is imprisoned for her pains.

On a hyper-modern all-white set, with bright light standing for the presumably Caravaggio-like gloom of Galactia's painting, the drama is played out. Involved arguments about the nature and ownership of art are enlivened through bold, characterful performances: Robert Goodale pragmatic, self-pitying and remarkably likeable as the Doge; Tom Burke broody, charismatic and insufferably self-regarding as Galactia's non-talent lover and rival Carpeta.

Barker's prose is rarely less than purple, often lividly so. Melanie Jessop's Galactia gets a lot of it to speak on her way to jail, and, as with many rebel artists, a good chunk is self-aggrandising jabber.

At times my distaste for this rhetoric translated into ennui, but even when you're desperate for her to shut up, there remains an alluring, dangerous energy to the woman.

At the end, when she stands before her displayed painting, realising perhaps that her own political intentions mattered no more than the authorities', her quietness is as much a testament to the power of art as the many words which came before.

• Until 27 January (020 8985 2424, www.hackneyempire.co.uk).