London's annual Serpentine Pavilion should abandon its commitment to giving overseas architects their first English commission and instead prioritise experimental, purposeful architecture, writes Phineas Harper.

It's hard to pinpoint exactly when the Serpentine Pavilions got dull. Another structure has just opened on the lawn of J Grey West's 1934 tea-rooms-turned-gallery, but does the series still mean anything? Over two decades in, can west London's pavilions programme still move audiences, or is the annual commission running on the fumes of nostalgia for lost glory days?

This year's pavilion, the 23rd in the series, has been designed by South Korean practice Mass Studies. It comprises five roughly triangular black-stained timber portals forming a star around a circular void with cement paving throughout.

The last great Serpentine Pavilion was 2014

Each portal has a slightly different function, paired with a slightly different facade. There's a wide, sittable portal with translucent pink walls; a tall portal with orange mesh walls; an obligatory coffee portal with tinted glass walls, and so on.

One portal (with black timber walls) houses a "library of unread books" where visitors leaf through donated volumes before wandering off. "It's not really clear what this is," I overhear an invigilator remarking. "You can donate books but can't take them away – that concept doesn't make sense to a lot of people. There is also nowhere to sit. There's only three stools and I'm sitting on one of them."

Elsewhere there's a child-friendly day-glo climbing net. A nice alcove of inclusivity to park the kids in while buying overpriced cortados in the coffee portal, but it's a pale shadow of the more expansive playable architecture local practices like Muf, Erect, Assemble or Edit concoct elsewhere.

If this year's pavilion is a dud, when was the last time the Serpentine delivered a banger? Certainly Bjarke Ingels's swoopy corridor of cleverly engineered fibreglass crates in 2016 or Selgas Cano's oil slick plastic tunnels the year before moved precisely no one.

Theaster Gates' brooding black collab with David Adjaye (built shortly before he ended his relationship with the gallery following sexual assault allegations, which he denies) felt like a rehash of the artist's 2017 brick cylinder in Wisconsin, swollen to inferior proportions to accommodate hobnobbing. In a trenchant 2021 essay the architect Douglas Murphy characterised Counterspace's canopy of steel scaffolding clad in rendered plywood shapes as "the sort of work students often come up with before they've had any experience" – ouch!

And I'm not the first to ask whether the Serpentine Pavilions have lost their relevance. Owen Hatherley labelled them a "combination of celebrity and obsolescence" years ago.

The last great Serpentine Pavilion was 2014. The giant glowing egg that Smiljan Radić perched on huge boulders like an otherworldly alien dolmen was genuinely electrifying. At dusk, the blob effused a rich atmosphere – weird, neolithic, intimate – while testing how to build with fibreglass in a novel way.

It's the brief itself that's to blame, worn thin after so many years of repeating the same trick

As with his Vatican chapel in Venice, the walls of which were cast using bubble wrap formwork, Radić understands that the only point in building a pointless building (and what else is a Serpentine Pavilion other than a pointless building?) is to treat the commission as a testing ground for construction experiments.

Yet multiple practitioners who've worked on the Serpentine programme tell me how dispiriting and opaque they have found the construction side of the commission. I had assumed the winning architects were empowered to build as they chose, appointing their own contractors and working closely with them to manage the build – how naive! Professionals who have worked on the programme say the architects get no real influence over the coterie of contractors that monopolise building each pavilion and control key design decisions.

All this isn't a criticism of the architects or curators who work on the Serpentine Pavilion. Each does the best they can within the constraining hand they're dealt. It's the brief itself – which sees an "internationally known architect" invited to create their first built structure in England – that's to blame, worn thin after so many years of repeating the same trick.

Is there hope for the ailing programme? Of course! The Serpentine Pavilion power players are perfectly placed to pivot. With a little more imagination, the pavilions could do so much more for architecture, the country and the climate.

Rather than jetting in overseas architects each time, for example, why not use the pavilions as a chance to seriously explore local materials: earth dug from the site? Straw grown in Hyde Park? Or how about taking the show on the road; building pavilions in different towns each year? What about a pavilion made entirely from salvaged material? A pavilion that leaves a landscape legacy? A pavilion fully dedicated to children?

There are so many possible briefs more compelling than the glorified Benugo hut that the programme has become today. Skilful architects thrive when they butt up against fiddly constraints, but against the backdrop of an increasingly complex world, the Serpentine's dogged reluctance to set a brief more innovative or timely than a pop-up party venue falls flatter each year.

Far more interesting is the explosion of architects inventing hyper low-carbon construction systems infinitely richer in tectonic expression and environmental performance. In one spring of crits I've seen more compelling ideas bursting out of British architecture schools than a decade of visits to Kensington Gardens.

In recent years, many smaller pavilions have been blossoming elsewhere. I vividly remember when Frida Escobedo's £680,000 Serpentine Pavilion, a pleasant but conservative arrangement of walls made from stacked cement roof tiles, was outshone in spades by Thomas Randall-Page and Benedetta Rogers' techno-piratical 'Antepavilion' – a floating inflatable theatre built the same summer on the other side of town at fraction of the budget.

Herzog de Meuron's Serpentine collaboration with Ai Weiwei could have made a fitting curtain call

Now more small pavilions are stealing the Serpentine's dimming limelight. This year eco hotshots Material Cultures have, in collaboration with Pakistan's Yasmeen Lari, built one in Barking with willow and reeds exploring how biomaterials could help defend against rising water levels. In Dalston, the London School of Architecture is unveiling a Toblerone-shaped "Hackney Pavilion" riffing off the timber frame of a nearby church.

In Lancashire, Ecaterina Stefanescu and Lee Ivett have built a temporary steel-and-timber community space alongside the Leeds and Liverpool Canal. All three structures have been developed in collaboration with nearby community organisations and feature locally relevant cultural programmes in the place of the Serpentine's VIP step-and-repeat. Even Studio Weave's upturned trumpet water catchers at the Chelsea Flower Show have more swagger while wrapping in a thoughtful response to ecological challenges.

It should have all been over in 2012. The faux archeological cork amphitheatre of Herzog de Meuron's Serpentine collaboration with Ai Weiwei could have made a fitting curtain call to the series. A pavilion whose shape was contrived by overlaying the footprints of its predecessors – implicitly suggesting the programme's past was perhaps more interesting than its future – would have been a respectful coda. Instead the pavilions lumber on into dwindling relevance, dragged behind a brief that has long since lost its mojo.

Phineas Harper is the former chief executive of Open City. They were previously chief curator of the 2019 Oslo Architecture Triennale, deputy director of the Architecture Foundation and deputy editor of the Architectural Review. In 2017 they co-founded New Architecture Writers, a programme for aspiring design critics from under-represented backgrounds.

The photo is by Tom Ravenscroft.

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