Need to know: The mission - Always a keen admirer of the decorative arts, Maggie O'Farrell decides to go under the needle

I have always wanted a tattoo. I know where I want it; I know how big I want it; I don't mind the pain. My only problem is what image to have.

In all other parts of my life I am decisive to the point of being reckless. But I have had, to date, three failed attempts at getting my skin indelibly marked. The first was aged 17 in a dodgy parlour with painted-out windows in Edinburgh; I nearly walked away with a permanent peace sign on my shoulder. The second was in Hong Kong where I came very close to letting a man who spoke only Cantonese draw a "good-fortune" fish on my bum. And then two years ago I found myself at a tattoo convention in Sausalito, California (don't ask), where I allowed a bloke in an unwise ginger goatee to go as far as inking a Chinese dragon onto my upper arm before I ran off to the bar.

So when I am given a mission to be tattooed, I decide that I've toyed too long with the world of body art. I must shake off my "blank" status (the trade term for the untattooed). It's time to go under the needle.

I select a piercing, scarification and tattoo parlour near my flat and venture in. It's an unpleasant hybrid of New Age and heavy metal - painted purple with mirrors, piercing rings, display cabinets and nasty fractal pictures lining the walls. The air is filled with a faint but constant humming. There's a man behind the counter with his bodyweight in metal hanging from his mouth and nose, and a scalp adorned with a spider's web. "Hi," I say, "can I get a tattoo done here?" "Where?" he says, scanning my body in the manner of a butcher sizing up a pig carcass. "Here," I repeat. He leans over the counter and stares harder. "Where?" he says again. I sigh. Am I really going to let a man with whom I am unable to communicate on a basic level decorate my body for life? "Here," I say slowly, pointing at the floor, "this shop." "Oh," he says, "yes."

We sit side by side on a leopard-skin sofa and he shows me "the books", which are the size of wedding photograph albums. They are filled with Polaroids of newly tattooed flesh - raw, reddened and slippery with sweat. On the other side of the room, a couple in matching fleeces earnestly discuss tongue-piercing with a woman in a pink wig.

"I was thinking of a flower," I begin, trying to ignore the familiar the-last-thing- I-want-is-a-tattoo feeling that always creeps up on me at this point, "an orchid or maybe a ... " "Do you know what would be really good?" he says. "A tiger. Lots of colour. Lots of animation. Across your stomach. Really, you know, animal." At this last word, I flinch, as if the power of him saying it can zap it there. He shows me a set of images that look like the kind of things Hell's Angels spray on their petrol tanks.

At that moment a man dressed only in a pair of jeans stumbles out of the back room. "Hey, hey, hey!" he yells, "whaddyathink?" He has turquoise spirals, inches thick, coiling from his wrists to his shoulders round and round his arms - the skin of which is puffed and red like unpricked sausages. The fleece couple look doubtful. "Great," the man next to me says, "fantastic." I head for the door.

Outside on the pavement, I revel in my state of blankness. Mission: failed. And I must finally admit, mission: aborted.