Made In Dagenham (15), Buried (15) (2/5, 4/5)

The true story of the 1968 Ford Dagenham strike, when 187 women machinists took industrial action and made national news, is one to lift the heart. It not only put a rocket under the bosses, it gave the whole country something to think about and heralded the coming of the Equal Pay Act two years later. It is a pity, then, that Nigel Cole's film Made in Dagenham contains so little of the inspiration and feistiness that drove those women onwards.

The problem is a familiar one in British film-making, it being neither funny enough as a comedy nor serious enough as a drama. And its ambition is so limited: it feels like the TV movie of a deeply mediocre sitcom. There are positives, however. Sally Hawkins is great as Rita, a cockney sparrow who turns tigerish in defence of her fellow machinists in Ford's dilapidated motor plant. Bad enough that they have to labour in cramped, airless conditions – a sweat shop, literally; now the management wants to exploit them further by reclassifying their jobs as "unskilled". Rita, inspired by union rep Albert (Bob Hoskins), takes the fight off the factory floor and into the boardroom, confounding both the old-school union backslider (Kenneth Cranham) and the public-school executive (Rupert Graves) who would carve up the power between them.

Despite setbacks at home, where husband Daniel Mays feels neglected – and possibly emasculated – Rita leads the women out on strike, and eventually secures an audience with secretary of state Barbara Castle (played with flinty gusto by Miranda Richardson). It should be stirring, and to a degree it is; but its narrative is all plod, and nuance is virtually nonexistent. The raucous chirpiness of the workforce, the meek silence of the union bigwigs as they listen to Rita's impassioned plea for support, the two junior ministers who mince around the queenly Castle – these are all creaky devices that undermine its essential good-heartedness.

The screenwriter William Ivory does what almost every Britcom resorts to and colours the air with profanity. And on another point of language: I feel sure the real Barbara Castle knew the difference between "credibility" and "credence". I liked the tentative friendship between Rita and Rosamund Pike's Biba-wearing trophy wife, though again I wasn't really convinced by it. The courage and solidarity of the strikers are saluted at the end of the film in interview clips with the actual Dagenham ladies, 40 years on. While it's touching to hear them recall the events they lived through, it does unfortunately compound the feebleness of the drama that preceded it.

Some movies seem to get made as a kind of stunt. The story goes that Joel Schumacher made Phone Booth because someone bet him he couldn't set a whole movie in one. But Phone Booth cheated by using flashbacks and cameras at all points around the street. Buried is a stunt thriller of much purer fiendishness. It begins inside a wooden box, and stays there, for just over 90 minutes.

Its premise draws on many people's worst nightmare: to find yourself buried alive. That's the horrific situation of Paul Conroy (Ryan Reynolds), a truck driver who's been working for a private contractor in Iraq. He can't remember what happened after his truck was ambushed, but somehow he's ended up in a wooden coffin under a ton of desert sand. Once he's stopped freaking out and screaming, he takes stock of what's to hand in there: a mobile phone with a fading battery, a Zippo lighter, a pen, a knife, a hipflask. That phone becomes his desperate lifeline, of course, kindling a spark of hope that's almost instantly snuffed. He calls 911, but what's the use if they're in Ohio?. He calls his wife, who's out; he calls colleagues, employers, the FBI, and we begin to learn the real agony of non-communication. "Don't put me on hold!" he cries. But then someone calls him, a foreign voice demanding a ransom for his life: it's the Iraqi insurgents who abducted and buried him. Now it's not just the lack of oxygen that could kill...

Rodrigo Cortés, who shot the film in 17 days, made his canniest decision in refusing to show any scene above ground. We are put right inside that box, and at least halfway inside Paul Conroy's head as he yearns for escape. Working in such a tight space demands ingenuity, and Cortés and his team are equal to the task. Chris Sparling's script is an infernal machine that starves the audience of oxygen right along with that coffin. Cinematographer Eduard Grau works eerie wonders with only the mobile's screen light and a Zippo for illumination. As for Ryan Reynolds, he has wiped the slate clean at a stroke for all those grim romantic comedies stacked against him. Considering he's lying flat for 90 minutes he conveys everything one might feel in such a predicament, starting with wild panic, then modulating through frustration, fury and despair. Cortés's remark that Reynolds returned from the shoot to LA "a physical wreck" should not be doubted.

Only once does the film make a false move, the more surprising given how disciplined everything else has been. After another heartbreaking setback, the camera pulls upwards and away from Reynolds, isolating him, but the height it reverses to suddenly breaks the illusion of containment that Cortés has been so careful to maintain. It's a small mistake in a film that brilliantly finesses the limitations of space into a haunting claustrophobic potency. This minimalist frightener is all about thinking inside the box.