MONDAY SEES THE announcement of the winner of the Turner Prize, the predictably controversial modern-art award, even though none of the nominees is terribly controversial. So the judges would do well to consider a late contender who has entered the fray with an audacious piece of work in the past week: the mysterious reimagining of Stonehenge on a hill on Achill Island, in Co Mayo, by the serial controversialist Joe McNamara.

Dubbed Achill-henge by locals, the huge structure was erected by McNamara and his associates last weekend on a scenic hilltop overlooking the village of Pollagh, despite attempts by Mayo County Council to halt the work.

Cynics might suggest that this is just another stunt from a publicity-seeker who is bitter at losing a fortune in the property crash and who reportedly owes Anglo Irish Bank €3.5 million.

That’s an understandable evaluation of the Galway-based developer’s motives, but the more artistically sensitive among us should now appreciate that McNamara is actually one of our bravest creative souls, pushing the boundaries of installation art – and indeed of performance art – in this country.

Operating under the nom de guerre “the Anglo avenger”, McNamara has displayed a flair for site-specific installations in the past. His series of pieces featuring his concrete mixer – first at Anglo’s branch in Galway city, then, more ambitiously, at the gates of Leinster House – demonstrated a keen eye for context and composition. The stark red lettering on the side of his truck – saying “toxic bank Anglo” and “500K for golf” – owed a debt to the declarative statements of the acclaimed US conceptual artist Barbara Kruger, while reconfiguring the form for post-Celtic Tiger Ireland.

In September of last year McNamara parked a slogan- emblazoned cherry picker outside the Dublin headquarters of Anglo Irish Bank, before parking it outside the Dáil on the morning of last year’s budget speech and playing music from the cage. (He is an accomplished uilleann piper: another example of his creativity.)

Presciently, one of his signs that day read: “To the politicians who vote for the budget today, the people will vote you out tomorrow.”

Like many profound artistic statements, Achill-henge’s impact was immediate, with a striking image of the circle making the front page of this newspaper on Wednesday. It struck a chord not just because of its vast scale (at 4.5m high, 30m in diameter and close to 100m in circumference, it’s a big ’un) but also because of the clandestine nature of its construction. This involved 30 trucks being driven from Galway loaded with concrete slabs and a team of workers operating in the gloaming of a late November weekend.

Above all, the structure demands interpretation, and McNamara invites the audience to project its own meaning on to the sculpture. Is it a shrine to the folly of the ghost estates that litter the country and despoil our landscape? Here, echoing both Stonehenge and the Poulnabrone dolmen, in the Burren, Achill-henge takes its lineage from those ancient burial sites, acting as a metaphorical grave for the hubris of our property bubble.

Or is it a modern-day fairy fort, with cold concrete supplanting organic trees? Does it represent a scathing critique of how we have forsaken our heritage for the unattainable chimera of property wealth?

Is it synchronised with the angle of the sun for the summer and winter solstices? In which case, as a giant sundial, it doesn’t so much tell the time as tell the story of our times. In attempting to be in harmony with the sun and yet disharmony with nature, it points to the inconsistency in all of us. Like any great artist, McNamara speaks through his choice of material, and the forbidding slabs of concrete speak volumes: they are a brutalist affront to the landscape that surrounds them. (An interesting detail was the “believed cost” of the structure, widely reported to be in excess of €1 million, though McNamara has asserted that the actual cost was closer to €20,000. The difference between the first figure and the second is itself a commentary on the imaginary property prices we were willing to believe in.)

If anything might damage McNamara’s Turner chances, it’s the remote location – if Achill-henge were in the Turbine Hall at Tate Modern, his name would be on the £25,000 cheque already. But the location is integral to the artistic success of Achill-henge, and McNamara has shown himself an astute judge of location. He is, after all, one of our finest performance artists, asking profound questions about the shape of our society, the fairness of our legal system, and our relationship with capital and land.

Of course, maybe a friend dared him to go mad with some leftover concrete slabs, in which case the Turner nominees can sleep easy until Monday. But perhaps pretending to be partial to a few headline-grabbing stunts is just part of McNamara’s performance, another layer to his creative expression. As in everything, that’s for the audience to decide.

Shane Hegarty is on leave