What a prize mess: The Stirling Prize

The Stirling Prize, British architecture's equivalent of the Booker, will be announced at a televised beano at London's old Billingsgate fish market tonight. The arcaded halls will hum with febrile expectation. But of what? Is this British architecture at the cutting edge, or trapped in a carefully stage-managed and institutionalised view of good design in the 21st century?

There are six buildings in the running: the Fuglsang Kunstmuseum, Denmark, by Tony Fretton Architects; Maggie's Centre, London, and the Bodegas Protos winery in Spain, both by Rogers Stirk Harbour + Partners; the Liverpool One Masterplan by BDP; 5 Aldermanbury Square, London, by Eric Parry Architects; and Kentish Town Health Centre, London, by Allford Hall Monaghan Morris.

The Booker distils internationally outstanding fiction into a shortlist through a lengthy and rigorous critical process. By comparison, the Stirling's shortlist, though not bare of fine architecture, seems largely an exercise in constrained worthiness, tainted this year by pathetically huffy charges of manipulation concerning the judging panel. The Prince of Wales, accused of similar interference over the Chelsea Barracks development, must be dunking his Duchy Highland All Butter Shortbread into the steaming Assam with unusual pleasure.

The Stirling Prize, first awarded in 1996, has lost its potency. Its shortlists have become decent, rather than battle cries for buildings whose relationships between people and places are genuinely exploratory. Where is the architectural joy – or risk? Where is the buzz that proclaims that British architects are seriously challenging the zeitgeists and physiques of our towns and cities?

The Stirling is awarded to "the building which has made the greatest contribution to British architecture in the past year". But if you asked 50 of Britain's most talented younger architects which buildings these were, most would surely cite projects, and architects, from other parts of the world as their inspirations. The Stirling Prize shortlist has rarely, for example, contained a building of such urban, spatial and material brilliance as the Kolumba Kunstmuseum in Cologne by Peter Zumthor. The Swiss designer is a hero to many of Britain's most thoughtful young architects, but the only architects on the 2009 Stirling shortlist who have comparable status in this respect are Eric Parry and Tony Fretton. They are architectural explorers. They take risks.

Parry's ability to untangle the complexity of historic sites and urban situations and layer 21st-century presence into them with artistry and subtly surreal provocation is unmatched in Britain. On a horribly herniated site in the City, Parry's Aldermanbury Square building may be an office tower, but it's richly engaging. Fretton, a burly and taciturn ex-performance artist, has become legendary for pared-down surfaces and details that create strangely tense confrontations between people and spaces: his interiors might almost be stage sets from a existential crisis filmed by Ingmar Bergman. It takes a brave architect to strip away comforting details and set up scenes that question the very meanings of space, surface and physical narrative – a compelling subject in a world dominated by controlled "public" realms, surveillance, and branding.

No major architectural risks are taken in the other projects in the Stirling Prize shortlist. The Liverpool One regeneration scheme may be great news for comfortably off shoppers from Cheshire and the Wirral, but why celebrate architecture that promotes nomadic wandering in our urban habitats, from one mirage of special offers to the next, soundtracked by the deadly bat-wing whirr of ATM machines?

Rogers Stirk Harbour's Protos winery in Spain, and their Maggie's Centre, a support unit for cancer patients at Charing Cross Hospital, London, are highly accomplished modernist buildings. But the extraordinary structural virtuosity of the winery almost belongs in a vast display case; and despite the calm elegance of its spatial connections, the Maggie's Centre has the unmistakable ambience of an architect's dream home in Fulham Palace Road.

Kieran Long, the editor of The Architect's Journal, skewered these two projects, describing them "as a vote of confidence in poor, beleaguered millionaire Richard Rogers, after being beaten up by Prince Charles in recent months". This predictably choleric barb obscures the key issue, and he's closer to the mark when he says that the Stirling Prize shortlist has "everything to do with the jury being given a bit of everything".

And in the "bit of everything" stakes, the Kentish Town Health Centre, designed by Allford Hall Monaghan Morris is the exemplar. AHMM have become one of the most shrewdly positioned operators among Britain's younger practices. They perfectly suit clients who want creative-looking buildings by personable architects who aren't suddenly going to start quoting Heidegger, or wondering if a building could embody William Blake's vision of the reunion of the body and the soul.

The Kentish Town Health Centre is a controlled exercise in voids, cross-connections, and internal natural light. Yet it's hard to see how this building is a markedly more ambitious contextual achievement than, say, the practice's Jubilee Primary School in a deprived Lambeth neighbourhood. That design got nowhere near the Stirling shortlist in 2003.

Great architecture is not about political correctness, or architectural positioning. It's about creating new kinds of engagement with people and places: genuine architectural experiments that may or may not succeed, yet have the potential to produce buildings and re-energised settings that thoroughly question the way we live – and whether we think architecture does, or doesn't, play a meaningful part in our lives.

The RIBA should ask the last six winners of the Young Architect of the Year competition to pick the 2010 Stirling Prize shortlist. There would almost certainly be a punch-up in the jury room, but it wouldn't be about the shoring up of established mindsets. The body and the soul of British architecture needs something of William Blake's visionary fire, after all, though it will not burn bright in the fearful symmetries of Billingsgate tonight.

The award ceremony will be shown on Channel 4 at 8pm tonight