In these health-conscious times, potato crisps have a bad reputation. Gone are the days when you could walk down the street cheerfully snuffling through a pack of Smokey Bacon. Try that now and people will stare at you like you're shooting heroin directly into a genital vein.

The standard tuckshop brands of crisps are shameful things, to be eaten in secret on a car journey. Of course, the fey "gourmet" varieties - thicker, hand-cooked "artisan" crisps with flavours such as Aged Stilton and Ambassador's Port - are still considered acceptable by the food Nazis, provided they're served in a bowl at a cocktail party, surrounded by organic vol-au-vents and snobs. That's because our food neurosis is actually snootiness in disguise.

Consequently, the cheap end of the crisp market has to pull stunts to distract you from the crushing social disgrace involved in actually purchasing a bag. Walkers' latest wheeze is a fun competition. Stage one: they ran adverts inviting the public to suggest exotic new taste sensations. Stage two: they chose six finalists, released them into the wild, and asked the public to vote for their favourite. Stage three: the votes are counted and the top flavour becomes a permanent member of the Walkers line-up. We're currently in stage two.

To lend the enterprise some gravitas, on the Walkers website you can watch kitchen surrealist Heston Blumenthal discussing the new flavours as though he genuinely believes they're edible. But are they? As the nation's foremost investigative journalist, I decided to find out, by buying a packet of each and sampling them. It was a mission that would take me to the very heart of a newsagent's and back. Here are my capsule reviews of the six competing varieties:

Builder's Breakfast

There's some confusion over the exact contents of the Builder's Breakfast. On the website, Heston claims they taste of "sausages, bacon, eggs and beans", whereas the packet itself lists "bacon, buttered toast, eggs and tomato sauce". This would imply that even Walkers don't know what they've got on their hands, possibly because the crisps themselves taste of stale fried egg and little else. It captures the feeling of sitting in a greasy spoon, being dumped via text while your food repeats on you. Depressing.

Crispy Duck and Hoisin

A fairly accurate rendition, although if you close your eyes they taste like the standard Roast Chicken flavour might if the "chicken" in them had been killed with a hammer made of compacted sugar. This is probably something Heston actually does in his restaurant.

Fish and Chips

Sounds like a good idea, but think about it: FISH CRISPS. Consequently they smell vaguely infected. Actually eat one and it's like kissing someone who's just eaten a plateful of scampi. Halfway through they belch in your mouth.

Onion Bhaji

The most convincing flavour, but they taste watered-down; as though Heston boiled one tiny bhaji in a swimming pool full of Evian, and then dipped some potatoes in it. It's like a lame TV movie about onion bhajis, starring Adam Woodyatt, with a soundtrack consisting entirely of library music, broadcast directly on to your tastebuds.

Cajun Squirrel

Self-consciously "wacky" and attention-grabbing entry. Walkers are keen to point out that "no squirrels were harmed in the making of this crisp", which is a pity because I had chucklesome visions of thousands of live, screaming squirrels being bulldozered into an immense bubbling cauldron in front of a party of horrified schoolchildren. The flavour itself is truly vile: if they'd called it Squirrel's Blood, everyone would've believed them. They taste precisely like a tiny cat piping hot farts through a pot-pourri pouch into your mouth.

Chilli and Chocolate

Excreted Battery Acid, more like. A boring lunatic with halitosis explains the smell of charred wood to your tastebuds. It's vaguely like the smell you get when you bleed a radiator, but sharper, more disgusting, and worryingly "human". They should've called it "Dirty Protest" instead.

So there you have it. They're uniformly horrible. Worst of all, none are a patch on, say, standard Salt and Vinegar, which has been around since the Cro-Magnon era. Obviously, they should've chosen more ambitiously. Since the squirrel flavour doesn't actually contain any squirrel, they could unleash other tastes you're vaguely curious about, but would never actually eat, like Cyanide and Lemon, or The Late Marilyn Monroe. If they'd bitten the bullet and genuinely released a flavour called Dirty Protest, people would queue round the block to try it, provided the packet carried a prominent guarantee that it was merely a simulation, not the genuine article. (For the record, according to The Encyclopedia of Unusual Sex Practices by Brenda Love [ISBN 0 349 10676 2], "faeces supposedly has a charred or sour flavour but otherwise tastes similar to whatever was consumed". So now you know.)

Or maybe they could've worked on flavours that evoked a time and mood instead of mimicking an existing substance. Who could resist Wartime Romance (cigarettes, lipstick, and railway station)? Or Studio 54 (cocaine, sweat, and Bianca Jagger)? Even Medieval Times (mud, gibbet and wet tunic) would be worth trying.

But no. They didn't dare to dream. So in summary: don't vote for any of them. Spoil your ballot paper instead. Because that's what they've done to these innocent potatoes. The bastards. The absolute unconscionable bastards.

• This week Charlie finished the seventh series of The Shield: "A brilliant final reckoning." He also spent about 97 hours desperately washing the taste of crisps out of his mouth: "The combined effect of all those flavours is like eating 15 bad orchestras made of tinfoil and grease."