Thomas Sutcliffe: How not to end it with a bang

I can't tell a joke to save my life, so please don't complain to me if I've mangled this one... which has been, in any case, pieced together from unlabelled fragments in my memory.

It concerns the freefall enthusiast who boasted to a friend that he had all but mastered the ability to jump from 10,000ft without the use of a parachute. The technique was 99.99 per cent perfected, he told his friend; it was just the last 12 inches of the jump that were still giving him trouble.

And this gag, or at least a dismembered ghost of it, came to mind while watching Steven Hevey's play In My Name at the Trafalgar Studios last week. There's no shortage of playwrights who can exit the plane, I found myself thinking as the actors took their bows. It's walking away from the landing that's the really difficult thing.

The thought had been prompted by a very familiar experience in the theatre, and one that's even more familiar in small studio spaces like the one in which Hevey's play was being staged, because they tend to be the preserve of less experienced writers. You sit down for the first act and find yourself in freefall – in Hevey's case, in a grotty basement flat with two ill-at-ease characters who are soon joined by a third who doesn't get on with either of the first two.

And so far, so good. The characters were intriguing and the dialogue – a kind of grungy naturalism – plausible and engaging. There's an interesting bit of business with a children's guessing-game; well below these characters' age range, but provoking unexplained jolts of feeling from them and some unresolved speculations about identity and prejudice in us. It's also funny and – I would say – clear evidence of theatrical ambition and ability. Then you file out for the interval, and when you come back in it is soon clear that you are going to be made to pay for the good time you had in the first act.

A gun is pulled out and the simmering violence of the first half boils over and hisses as it hits the hob. The dialogue tightens a little, purposively, narrowing down on the target it always had in mind. And then, as the playwright experiences ground-rush – that moment in a parachute jump when you are suddenly aware that you're not flying but falling and you'd better pull the ripcord – there's a sudden flustered blizzard of resolution as the characters tell us, with the explicitness of someone making a platform speech, just what it is that we're expected to take away from the event.

And, as I say, this isn't an uncommon dynamic in the theatre. You start with insinuating life, significant in ways you can't yet fully understand, and you conclude with declamatory art, not exactly dead but certainly a good deal less sprightly than it was when it started out. And it's usually the last 12 inches that do the damage – the way that the approach of the ending pressures a writer into making decisions that he or she may not yet be ready for. Gravity suddenly re-asserts itself and you can almost feel the slump downwards.

I'm not sure that there's an easy way round it, other than learning the hard way how to hit the ground gracefully. Pop songs can dodge the crunch by going for a fade (or, in the concert hall, a brief crescendo and out), but I can't be alone in thinking that's a kind of cheat – and one that's scarcely available to a playwright, even if it is standard operating procedure for soaps.

Occasionally, you come across a writer who sidesteps the difficulty by giving you two incompatible endings, as John Fowles did in The French Lieutenant's Woman (privileging one over the other on the basis of a coin toss), or as Adam Thorpe does in his latest novel The Standing Pool – another book that has its cake and eats it. But that too is scarcely practicable for the jobbing playwright, who, outside of the realm of meta-theatrical experiment, will have to rule out countless tantalising possibilities by choosing just one.

And don't think I haven't noticed that these harsh realities apply to columnists, too. What's the altimeter reading now? I know that time is running out... that I have to start thinking about getting my feet together and my knees bent for the impact. Ideally, I'd like to hit the roundel in the landing zone dead centre – discovering some final sentence that would give the impression that this was precisely where I'd been aiming all along... though the truth is that columnists usually paint the roundel in only after they've landed. I fear I may not have time even for that... Oh sh...