As found spaces go, the Paintframe is pretty spectacular – and the National didn’t have far at all to go to find it. Situated on the east side of the South Bank complex with a tiny box office and entrance wedged down an alley beyond the Cottesloe, it’s converted from the NT’s scenic studio where large-set canvases are normally hung and painted.

A trail of paint leads audiences to the venue, and paint cans, brushes, rigs and other industrial equipment remain scattered about, reminding you of the space’s customary function. Temporary bench seating with un-upholstered cushions adds to the rough-and-ready feel.

Normally, the public would only ever see the Paintframe on a backstage tour. The Double Feature season offers a chance not only to see it, but to see it put into thrilling action. Each of the four plays has a different set, assembled and dismantled before every staging. During a 20-minute interval, the audience must leave their seats, taking all belongings with them, while technicians scurry hurriedly about transforming the cavernous hall.

During the break, I highly recommend that you grab a drink and head for the viewing platform to listen to the live jazz band entertainment and admire the stagehands’ efforts, and also check out the building model in the corridor to get a feel for the scale of the project.

The four pieces – Sam Holcroft’s Edgar and Annabel and DC Moore’s The Swan as the first pairing and Prasanne Puwanarajah’s Nightwatchman and Tom Basden’s There Is a War - are a mixed bag, all produced to the highest quality under the direction of Polly Findlay (Swan/Nightwatchman) and Lyndsey Turner (Edgar/War).

For my money, Moore’s The Swan is the most dramatically promising. Set in a down-at-heel London pub on the day of a funeral, revelations about the deceased, an alcoholic hard man, have implications for the loved ones he left behind. There are nicely drawn characters that a fine cast, including Trevor Cooper, Pippa Bennett-Warner and Sharon Duncan-Brewster, can really get their teeth into, palpable tension and two delicious comic cameos, delivered by Nitin Kundra and Claire-Louise Cordwell, as a hungover nimwit and his ballsy bird.

Of the others, Puwanarajah’s one-woman Nightwatchman receives a muscular rendering from actress Stephanie Street, but feels more like an extended sport (cricket) and history (of the Tamils in Sri Lanka) lesson than a play.

Holcroft’s Edgar and Annabel is certainly intriguing: what seems to start as a Pirandello-like piffle turns into a sinister conspiracy plot to overthrow a corrupt government. It’s linked thematically with Basden’s sweeping satire There Is a War, in which two indistinguishable forces engage in brutal and unending battle under inept leaderships. The latter boasts moments of hilarity but is pretty thin. It’s fast jokes and writ-large message – war is a meaningless and futile propaganda exercise – and not much else.

Do watch out for the talented, multi-tasking author, though, who appears in both his own play (as a clueless general) and in Edgar and Annabel (as a karaoke-singing bombmaker).

If I had to give scores on the doors for each, I’d award four stars to The Swan and three apiece for the others. But the Paintframe experiment is five-star all the way. And, in addition to whoever at the National had the idea for it in the first place, the real star of the project must be Soutra Gilmour, who designed the sets, costumes and general “environment” for the entire undertaking. An extraordinary and thrilling achievement.

And, sadly, a short-lived one. The Paintframe must return to its normal use soon – the National are currently having to ship out to the Old Vic for scene paintings during this season - so take advantage of this unique opportunity while you can.