Thursday is a big day for me. So big, I find myself getting up earlier than usual to make it into work a whole hour before I need to. Officially, this strange event occurs because this magazine is on deadline, and I am a thrusting young journalist keen to make my mark. Unofficially, it’s because my internal shopping clock knows that Topshop updates its website every Thursday. And, along with an increasing pool of money-haemorrhaging, purchase-obsessed souls, I am an internet-shopping addict.

Last year, nearly one pound in every seven spent on consumer goods in the UK was splurged on the internet, with the ratio predicted to hit one in five this year. In January, monthly sales reached £4.5 billion. For many of us, though, that figure comes nowhere near revealing our true obsession with online shopping. It is a phenomenon that encourages people to indulge in their darkest retail fantasies – and it throws up some pretty odd behaviour along the way.

First comes a spike in crazy spending habits.

“When we launched the website, we were expecting to sell jeans and T-shirts,” says Tom Chapman, the owner of Matches and its online bigger sister, Matchesfashion.com, “but people are buying big statement pieces.” By that, he means the Zagliani puffy bag (at £1,500 a pop) that one customer orders in each colour as soon as they hit the site, and the big-ticket items that make up the huge orders regularly placed by an infamous American rock star at 4am, which need to be shipped in several suitcases.

The virtual removal from the painful process of payment has a lot to answer for here. Given the ease of a couple of clicks, the link between funds lost and fun gained seems so tenuous, it hardly feels like spending. There is no standing in a queue and giving your conscience the chance to get the better of you here. What’s more, by the time the packages actually arrive – all nice and pretty and wrapped up like presents – they seem almost free. Shoppers like me suffer “payment lobotomy”, erasing the minor detail of money from our memories.

While self-deception may be a useful attribute, internet consumers are savvy. They keep tabs on their favourite sites with organisational skills worthy of a Navy Seals operation. Erin McGann, who works as an editor at the Southbank Centre, has hers bookmarked on her computer, ready to check as soon as she gets to work. “It’s terrifying, but I’ll check them before I read the news,” she says.

I have a wish list of items permanently on hold at Net-a-porter.com, ready and waiting to be summoned to my wardrobe on payday. We are not alone: according to Sarah Curran, the founder of My-wardrobe.com, her biggest orders are taken on a Tuesday – new-stock day – thanks to customers waiting to pounce.

And pounce we do, literally, the minute we see something on a catwalk, page or street that takes our fancy. The internet shopping revolution has encouraged those of us who have never set foot in the personal shopping area of a department store, let alone shopped the catwalk, to browse next season’s look books. It taps into our inner Veruca Salt, allowing us to act on those need-it-now impulses that hit as soon as we catch sight of that dress. It’s why £800 It bags sell at the rate of one a minute on Net-a-porter.com, and it’s what makes one international royal get her PA to e-mail a shopping list of her picks from the weekend papers to Matches every Monday.

Shopping has long been viewed as something that offers comfort in times of need, loneliness, boredom or inebriation, and now the door is open 24/7. All these sites see extensive activity throughout the night – I, for one, have bought a couple of rather dodgy outfits after a bit of online activity that took place the wrong side of the pub.

Nestled in our sofas, we create our own perfect retail experiences, without fear or embarrassment of being caught. One friend puts on each outfit she has ordered, then practises walking into her sitting room as if she’s greeting people in a bar – hand held aloft in a wave and all – before deciding what to keep. This process would surely be difficult to replicate in a crowded changing room, not without security being called, at least.

In her own home, though, security aren’t there, it’s just her and her pretty boxes and her slinky bits of ribbon, and the sheer joy of her new clothes, having totally forgotten that brief moment in which she handed over her credit-card details. Nothing – not the size-eight teenager with smelly feet in the changing room next door, the irritating shop assistant who tries to coerce you into high-waisted tartan trousers, nor the weird mirror that makes you look like an even lumpier Jade Goody – can ruin that moment. Until the bank manager calls, that is.

1. Strappy sandals, £313, by Biba; www.my-wardrobe.com, available Tues at noon.

2. Strapless dress, £750, by Luella; www.net-a-porter.com, available Wed at 2pm.

3. Dress, £358, by 3.1 Phillip Lim; www.matchesfashion.com, available tomorrow at 3pm.

4. Floral skirt, £45; www.topshop.com, available Tues at 6am.

5. Bag, £1,245, by Marc Jacobs; www.brownsfashion.com, available today

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