Dialogue heads in the right direction when the stars of Before Midnight are in the driving seat

Plus: A chocolate price that's hard to swallow and David Mamet plumps for (non)bio

Julie Delpy and Ethan Hawke talk – and talk– as Before Midnight’s Celine and Jesse

Let's take a drive and have a talk. It can be a good way to air an awkward subject, after all – both participants facing forward, sealed into a space that doesn't allow for interruption. In the right circumstances a car can turn into a confession box with pneumatic tyres, a place at ease with long silences – whether they're companionable or awkward – but also encouraging of revelation. It works for Richard Linklater anyway, in a showily unshowy sequence at the beginning of his latest film, Before Midnight. The scene lasts for nearly quarter of an hour – almost without a break – and is filmed throughout through the windscreen of the car.

It's the dullest kind of two-shot you could conceive of – two faces square on to the camera, only rarely turning to add facial expression to what's being said. And yet in Julie Delpy and Ethan Hawkes's performances, it's also riveting. As a narrow Greek road unwinds behind them, their relationship – its strains and strengths – unfolds too, taking a bend here and there, running straight and smooth at other times. It is simultaneously static and anything but.

Which is, I guess, why such scenes are so attractive to film directors, even if not many of them indulge their affection quite as fully as Linklater does. Cinema has always found the automobile seductive, of course, ever since the Keystone Cops first set one flivver in pursuit of another. But if you do an internet search for the cinema of cars, what you turn up is almost exclusively external, essentially a list of great car chases. That's hardly negligible, for an art form that has speed and movement knitted into its very being. But what doesn't get acknowledged, in those forums at least, is that the car has always helped cinema get more cerebral too.

There's a very long pedigree for that scene in Before Midnight, as I discovered when I tweeted a request for other examples of automotive conversation and ended up in a time-line traffic jam (thanks to all those who replied).

Linklater's scene, someone pointed out, is a knowing homage to the opening of Rossellini's Viaggio in Italia, in which Ingrid Bergman and George Sanders roll across the Italian countryside making small talk that hints at something larger. That's one of the virtues of the car interior on screen. It seems to stir thoughts of getting away in people, as if the changing landscapes around them generate some emotional wanderlust.

At the same time it's the most realistic forum in which two people can have a long conversation as a kind of secondary activity. Sit them down in a room together (as Linklater also does in his film) and it's hard to avoid the sense that conversing is what they're there for. Sit them in a car and – provided your scriptwriter is good – the conversation can flow from them like sap, a side-effect of confinement and time.

It doesn't exactly hurt that movement will add a vestigial flicker to frames that can be (for cinema at least) unnaturally still. Think of another scene mentioned by a lot of people – the climactic moment in On the Waterfront when Terry confronts his brother. In memory, I'd back-projected the city streets behind them, but Kazan's version is even starker than that. A slatted blind closes the space off, so that all you see is Steiger and Brando, their faces erratically splashed by passing street lights. And Charlie can do nothing but sit there and take the accusation.

But this perhaps drives too directly to its destination to be a classic driving conversation. Because the defining feature of this trope is unexpected detours. Think of Pulp Fiction, of Alexander Payne's Sideways, of Collateral and Cosmopolis.

When the camera climbs into a car you can never be entirely sure where you're heading, only that looking out of the window is the last thing you'll want to do.

A chocolate price hard to swallow

My ticket for the first night of Charlie and the Chocolate Factory featured a row of zeros where the price would usually be. I suppose you might defend the practice as segregating the critic from the sordid question of value for money. But later I discovered that taking a family of four to the West End's newest musical would range between £128 for the cheapest seats to a staggering £344 for decent ones. And then I thought of someone clicking "Buy Now" on the strength of one of the insouciantly over-generous reviews the show received. The price should be left on.

Mamet plumps for (non)bio

I don't often use the word "bullshit" on radio, but I found it hard to think of a better one when describing the disclaimer at the beginning of David Mamet's HBO film Phil Spector.

"This is a work of fiction," it reads. "It's not 'based on a true story'. It is a drama inspired by actual persons in a trial, but it is neither an attempt to depict the actual persons, nor to comment upon the trial or its outcome." Every word of which is true barring "not", "neither", "but" and "nor".

One understands the lawyers demand certain genuflections before the vengeful god of Prospective Litigation. But do they have to be so utterly ridiculous?