Lost Tribes: The Middle-Aged Women of M&S Marble Arch

If you've recently lost touch with one of your older female relatives, it's entirely likely that they've joined the nomadic, department-wandering women of Marks & Spencer, Marble Arch.

These ladies of a certain age were once innocent shoppers Up West, who were simply Having A Lovely Day In Town, until they wandered into the gilded palace of scones and were seduced by the cosy nightwear, comfortable shoes and extremely competitive basement coffee shop. Soon it was apparent that their every sensory need was being met somewere across the marbled floors of Marble Arch branch and they just never left. Meanwhile, in houses across the capital and the Home Counties, there are lone men opening and closing the fridge door absent-mindedly, dimly aware that something is missing.

I had this revelation as I was trying on shoes at lunchtime today. I was taking a walk around the second floor in some new heels and thinking 'Mm, these are quite comfortable' (of course they are, you idiot. It is only when you leave the shop that the spell is broken and the Grinding Cogs of Screaming Shoe Pain begin to turn) when I saw a mature lady sitting on the edge of a mannequin plinth, watching me intently. I smiled at her in a non-hostile way and eventually she smiled back. Ten minutes later, I walked back in a different pair of shoes and she was still there in exactly the same place and I realised, that is because she has been here for 18 years.

These women can be found roaming the floors day and night, pushing trolleys full of Useful Things and Lovely Treats that they've collected, like Bubbles from The Wire, with hair that is actually not dissimilar (albeit tonged and backcombed, not natural). Some members of the species live in isolation within the colony. Others prowl the aisles in groups of three or four, picking over racks of scarves and sniffing at foam bath like monkeys investigating an exotic piece of fruit, or calling out orders to meet at handbags in 20 minutes. They never sleep and they live off ham and fruitcake that they've scavenged from the food hall while the security guards are distracted.

They speak in many tongues, but they are generally friendly, if initially startling. While you are in front of a mirror, distractedly looking at your feet in grey patent sandals with a gold heel, and bemoaning the Curse Of Meaty Calves that has been visited upon you, you may hear an exotic call aimed at you from 15 metres away: 'TOO BEEEG, DARRRRLING. ONE HALF SIZE DOWN!' And you realise they are reaching out to you. It's exciting, of course, to find that you are communicating with them, but as they come closer and fully engage you in conversation, you start to edge away, realising that you're not like them, you're young and you belong in Selfridge's next door, with its exclusive perfumes and dangerous fashions and champagne bar. Don't you? And you turn and run away through smart trousers and umbrellas and slippers you will never wear, and they stare after you, thinking, 'You'll be back. And one day you'll be staying. You'd better like teacakes.'