Everyone likes to think they have a few guiding principles. Basic stuff like "no bitching about workmates" or "no flirting with estate agents." If you're a vegetarian, it's pretty simple: nothing with a face. You've chosen the meat-free life and you'll sure as hell stick to it.

Fast forward to the wrong side of a round of tequila slammers, though and the old moral compass inevitably starts to spin. But while the rest of us are chewing the bartender's ear off about how Sophie in marketing can be really two-faced sometimes and complimenting Jamie-from-Savills on his aftershave, what are those goody-two-shoes vegetarians up to?

Well, according to the results of a new survey, they may well be engaging in similarly weak-willed shenanigans. In a poll of 1789 British vegetarians, the VoucherCodesPro website (that well-known source on vegetarian eating habits) found that 37 percent of veggies eat meat every time they're drunk on a night out.

So basically, a third of all those people who have ever given you disapproving looks for asking for extra pepperoni on your Meat Feast regularly end their Fridays dropping a kebab down themselves on the night bus.

The survey also asked respondents how often they partook in such drunken meat binges. Thirty-four percent admitted to eating meat every time they were drunk on a night out, 26 percent said it happened "fairly often," and 22 percent said "rarely."

The same group of renegade veggies were then asked to reveal which foods they were most likely to eat after a night out. Would they go for a hand-reared Angus steak, nurtured on a family run farm in the Scottish highlands? Organic chicken breast? Sustainably caught salmon?

Nope. Kebab meat—that rotating siren to ensnare many an inebriated soul—came in as the number one late night snack, followed by beef burgers, and the veggie nemesis, bacon. Fried chicken and pork sausages also made the cut, rounding off a a flesh-filled top five that would push Morrissey into circulatory shock.

Finally, in order to fully shatter any illusions we had of the world being a nice place with a couple of nice people in it trying to help out the animals, the survey then asked these vegetarians whether they had told anyone about eating meat when drunk. Unsurprisingly, 69 percent said they hadn't, making them both compliant in the mass slaughter of animals and liars.

VoucherCodesPro aren't the first to question the commitment of those following a veggie diet. Last year, a study from the Humane Research Council found that five out of six Americans who are currently vegetarian will eventually revert back to omnivorous eating.

But for vegetarians still on the plant-based wagon—at least while sober—VoucherCodesPro founder George Charles had some words of advice for those tasked with walking them home. He told The Publicans' Morning Advertiser: "I think it's important for friends of these vegetarians to support them when drunk and urge them not to eat meat as I'm sure they'll regret it the next day."