Is this a lager I see before me, asks Peter Crawley

A couple of years ago, when an Irish theatre company read through a stack of new play submissions, one drama was scornfully rejected. There were plenty of good reasons to dismiss it - hapless plotting, leaden dialogue, etc - but the script actually drew gasps of disgust when it suggested that a particular beverage, mentioned throughout the play, might just as easily be changed to whatever brand name the theatre company could wring some sponsorship from.

That disapproval typifies the theatre's relationship with product placement. Movies may have long since sold their soul to clunky endorsements and commercial tie-ins. TV has never lagged too far behind, and even literature (if we accept Fay Weldon's The Bulgari Connection as such) has cashed in. The theatre doesn't like its muse to be quite so mercenary.

The stage has been largely insulated from embedded commercials, but that may be changing. One recent Dublin show prominently featured Heineken bottles, liberal mentions of the Four Seasons hotel and the Ice Bar, together with programme note shout-outs to Dubarry and Pamela Scott, among others.

Nobody spluttered in disbelief - the show was The Last Days of the Celtic Tiger, and the thought of a Ross O'Carroll Kelly play that wasn't dizzy with commodity fetishism is as inconceivable as Godot brought to you by FedEx.

There are more specific and unashamed mentions of Kimberley biscuits, Twiglets, Honey & Lemon Lockets, Kellog's breakfast cereals and even Complan in the plays of Martin McDonagh and Mark O'Rowe, but they aren't there to attract investment; they embroider the plays with the stitches of our consumer-addled pop culture.

In fact, a contemporary play is now more likely to draw attention to itself through product displacement; if a character orders a beer, say, without deciding which kind, it's a disjunction with reality. But if brand names are just part of our everyday dialogue, why should they bother paying for any onstage mentions?

For example, the Broadway musical Legally Blonde swirls with innumerable products, from Red Bull to Tiffany's necklaces, but didn't earn a cent for any of these inclusions - the producers decided that it wasn't worth asking.

Controversially, though, in 2005 the venerated playwright Neil Simon changed the script of Sweet Charity to allow a mention of Gran Centenario tequila (which did pay for the privilege), while just last month McCain Oven Chips - how's that for glam? - coughed up to have its wares featured in The Old Vic's 24 Hour Plays Celebrity Gala.

So, does it pay to advertise?

We may soon find out. With state funding for theatre receiving a measly 3 per cent increase for next year, theatre companies will have to become more resourceful in getting their shows up and running. Don't be surprised, then, if fewer companies scoff when a brand name surfaces in a new play and start considering their rates.