Harrods has a reputation to uphold. It's why the shop's staff dress code demands that men look "debonair", a word not used once since doctors were still recommending cigarettes to pregnant women. It's why they're "spending a fortune" on a massive new room to sell expensive wine in.

It's why, in 2017, they enforce a dress code on their customers; anyone in ripped jeans, high cut Bermuda or beach shorts, swimwear, athletic singlets, cycling shorts, flip-flops, thong sandals and dirty or "unkempt" clothing, technically, shouldn't be allowed in to browse Harrods' selection of bespoke Christmas tree baubles and £70,000 vases.

The whole thing seems bizarre when I hear about it, but a quick visit to their FAQs confirms it. How does it work? Are there bouncers turfing out 15-year-old emo kids because they have a few rips in their jeans; rejecting those adult men who buy and then actually wear lycra shorts for their ten-minute cycle to work; discriminating against crust-punks for being gross?

Obviously this won't cause me any problems: I dress like an aspiring Countryfile host. But what about my subcultural brothers and sisters? Are they bound to a Harrods-less existence purely because they align themselves with a certain way of life? I'm not sure, so I'm going to spend a day dressing up as various subcultures to see who Harrods victimises and why, attepting to get in, get assistance and sample the products in each guise.

MOD

Mods have been a mainstay in London for decades. You're as likely to see one, with their funny sideburns and fascistic approach to tailoring, nodding down Carnaby Street today as you were 50 years ago. There's no chance we're having problems here.

GETTING IN

My first appointment at Checkpoint Charlie. Coming around the corner, I spot him. The Stasi man, thoroughly groping a Lonsdale Bag. I approach.

More Gourmet Burger Kitchen than Berghain.

Result: PASSED

GETTING HELP

I've never been here before. This place is impossibly weird. Basically Bicester Village with more Egyptian-themed escalators. An absolute a vacuum of culture. There's so much stuff, but absolutely nobody is interacting with it. And now I'm about to join them.

"Fifth floor, at the back."

Result: PASSED

SAMPLING STUFF

I follow my nose to Fred Perry. Are they going to let me – mod me – try on just any old £80 T-shirt or £120 sweater?

Apparently this shirt "smashes it, but could be tighter". Couldn't agree more; you could barely see my nipples in this one.

Result: PASSED

So mods are fine. But we knew this. Your dad dresses like a mod, in that he occasionally wears a collared shirt. If Harrods didn't sell your dad and other dads scented candles and souvenir teddy bears the place would shut. So let's treat the mod as a control. Now, time for something comfier.

NEW AGE HIPPY

Here he is. Was out for the count in his tent, and then – just before midday – heard some Opus III tune and slithered out. Now he's eating wheat germ and tempeh, and entering conversations he's convinced he's a part of.

GETTING IN

With my flat feet slapping the streets of Hans Road, an old man sips a cappuccino and squints at me. Approaching the door, I brace myself.

Absolutely nothing.

Result: PASSED GETTING HELP

My gigantic white feet take me up the stairs to the only place in SW1 that you might be able to find wince-worthy conversations about ley lines and CND: the Halcyon Gallery.

Here, I'm going to have myself a little chat with one of the in-house people.

"Afternoon," I say. "I wanna see the most far out material you've got here."

"Of course." She shows me immediately to some kaleidoscopic imagery and Rothko-type prints. Distinctly "wizard" and "dope", I say.

"So what is it that you're looking for?"

"Something to chill out to. Something with good balance and vibe."

"Well, have you seen this Lorenzo Quinn piece?" It's a gyroscopic, bronze-type structure. It is pretty sensational, actually, but nearly £55,000. I'm in central London and I'm not wearing shoes; safe to assume I don't have a lot in my savings.

Result: PASSED

SAMPLING STUFF

Half an hour down and New Age Hippy me is hungry. I make my way past Café Godiva (£8.50 for a mocha) and end up at a chocolate counter, where I'm given a passionfruit number no questions asked.

Result: PASSED

Well, thus far, it looks like the systematically discriminatory vision of Harrods I had simply isn't true. It's a liberal paradise; a mecca for the minted and the misfts. Nothing seems to phase them, so may as well wheel this one out:

CYBER GOTH

Plucked straight out of a Death Note comic; a neon figure taken from a Games Workshop and placed on the dark blue bit of the Monopoly board. I stomp past in boots; people are confused. Perhaps they think they're staring at a rare funghi growing from a pair of jorts? I don't care, because where I'm going, there are no rules.

I walk up to the door.

GETTING IN The man in the dark green jacket holds it open for me. I walk through, confidently.

"Sorry, mate." I stop. "I can't let you through like that."

"What, why? What do you mean?"

"I can't let you through."

"But why?"

"You're far too… naked." I recoil. "Can you step outside, please?"

"But this is who I am." His arm stretches out across me; he starts muttering into his radio.

"Get a camera on me, please. Door number seven. Camera." I feel sweat on my back. "There's a GAP three doors down. They sell T-shirts for a few quid. Go get one, and then I'll let you through."

By the end of the sentence he's thrusted me through the door: it's game over.

Result: FAILED

GETTING HELP: N/A

Reader, if you remember anything from today, it's that Harrods discriminates against cyber goths.

If they want to play that game – sticking barriers up – then I'm going to kick the fucking door down.

PUNK

GETTING IN

With the spirit of GG Allin coursing through my veins, I swagger up to the doorway – and hear it.

"Excuse me."

"What?"

"Are those," he says under his breath. "Your clothes?"

"Yes."

"Those are your normal clothes."

"They are, yes." I feel my temples pulsing as we maintain eye contact. He nods me along.

Result: PASSED

GETTING HELP

What the fuck. I hadn't planned for this. Yet, strolling around in what looks like old Vivienne Westwood, I think, 'Where else can one go other than her concession?'

"Alright?"

"Hello," says the man.

"Have you got anything that would suit my 'thing'?"

He looks me up and down. "I've got exactly the thing!"

Result: PASSED

SAMPLING STUFF

"How about this WWII jacket? This is exactly your vibe."

"What," I say, "this vibe?" I tear my binbag open, his eyes open wide.

"Wow. Is that a tattoo?" I nod. "It looks great. It looks like it's bleeding! And it looks great with the jacket."

I'm gobsmacked. People walk past, but he doesn't give a shit. He keeps hurling more expensive garments at me – £900, £1000, £1200. People give aunty Viv a hard time for selling out and saying questionable things about people who cant afford to buy organic food, but hey, who knew, turns out she's still punk as fuck.

"I think you look amazing in this. It's so exciting."

Before I know it, I'm about to buy a £1,100 cardigan that I cannot in any way afford.

Reaching for my wallet, I snap out of it, saying I need to verify the transaction with my manager (?). He says he can wait, but – eventually – I manage to persuade him to just put one aside for me. Walking away, my heart whistles like a steam train,

How did he manage that? I'd try to pull the old punk-cockwomble stunt, and he'd transformed it into nearly plunging me deep into my overdraft.

Result: PASSED Walking through the store, people do look twice, but it doesn't matter. I've already solved this one: Harrods is kind of like Glastonbury. Once you get in, you can essentially do whatever you want – shovel a load of pingers down your throat, hurl glass bottles around and do as many keys as you like. It's just getting through the door that's the issue.

Leaving the place for the last time, I hear the security guard yell, "How did he get in here!"

You can't stop them all, pal.