They say there's no such thing as a free lunch but, when it comes to hotels, we want to have our complimentary coffee pods and drink them too!

Slip that plastic key into the door and suddenly self-respecting people become obsessed with tiny bottles of conditioner and wafer-thin shower caps. They lose sight of their objectivity and forget about the normal world that exists without mini-bars.

There's a clearly defined line between what you can and can't take from hotel rooms. If you're a little hazy on the fine print, this list should keep you on the straight, narrow and well conditioned.

Nobody is going to blink if you shove a few soaps in your toiletries bag, but pilfering the bible means your moral compass probably needs adjusting.

NO: Linen & Towels

Curtains, pillows, sheets, robes... Keep those sticky fingers at bay around these items. Only when you are staying on a champagne budget do the robes become take-home tokens. The slippers, however, are yours to keep.

Let sleeping towels lie. (Image: Getty)

According to the Huffington Post, the average hotel loses 10 to 20 per cent of its linens per month. Some hotels have actually started putting tiny tracking tags on their towels, robes and bedsheets, or offering the items for purchase like a hotel gift shop.

Also, they have your credit card on file and I'm guessing that well-used towel isn't worth what they're going to charge you. Fluffy towels are hard to resist, but investing in some fabric softener back home should see you right.

YES: Toiletries

I once found a hotel moisturiser I liked so much I collected four bottles in one night, and lived to tell the tale. Seriously though, the MALIN + GOETZ products at QT Hotels are divine.

Gotta catch 'em all. TOILETRIES! (Image: Getty)

Toiletries are fair game. They're disposable and can't be used by the next guests. Shampoo, conditioner, lotions, soaps... go for it.

Raiding the housekeeper's cart is generally frowned upon, unless you're pinching extra milk and tea (guilty) or like living on the edge.

NO: Appliances

One in five Brits admitted to pinching the kettle from their hotel room. Is there nothing those people won't for a cup of tea??

Who even has room in their luggage for a kettle? (Image: Getty)

Hair dryers, TVs, remotes, and lamps are a firm no. If a friend came to visit and nicked your bedside lamp, that would probably be a pretty short-lived friendship. Though I guess you wouldn't be charging your friend for the privilege of a sleepover.

Some hotels nail or padlock their appliances to the room. The others are trusting you to be a grown up.

YES: Stationery

Hotels brand these amenities in the hopes that you WILL take them. Pull out a Hilton pen or a Shangri-La pad and you've got an instant conversation starter and hopefully some positive word-of-mouth for the hotel.

Save the trees. Steal the notepad. (Image: Getty)

Working in the travel industry, our drawers are full of pens from hotels all over the world. This is one of my favourite pseudo-souvenirs. In front of me right now I have pens from QT, Pullman, Carnival Cruises, Travelodge and Novotel, and they each tell a story of happy times on land and at sea.

NO: Artwork, batteries, lightbulbs, door signs, crockery

Do you really need that generic landscape print? Are you that hard up for a pre-used light bulb or half-drained battery? This is shady territory and I won't have any part of it.

It's a sign! Leave it. (Image: Getty)

Put down the clock radio and step away from the coffee maker. Also, if you don't know by now that most of your mini-bar comes at a cost, you've probably already had one too many tiny tequilas.

Weirdest items stolen from hotels:

• A $300,000 Andy Warhol print from the W Hong Kong
• A Grand Piano from a Starwood Hotel
• A suit of armour from a Best Western
• A marble fireplace from the Four Seasons Beverly Hills
• A mini-bar fridge and sofa from a 5-star hotel in Dubai
• An entire dinnerware set from the Franklin Hotel
• 'Adult' toys from The Residence in Bath

Ross gets it... sort of.