Nearly three in ten (29 per cent) have even been forced to apologise to staff because of one of their fellow diners' appalling etiquette, the poll by software partner to the hospitality industry Fourth found.
It's hardly surprising, when 13 per cent of Brits have doused their meal in ketchup dining in a smart restaurant - and one in twenty have complained to staff because their red wine was warm.
One in twenty (5 per cent) of clueless diners have even mistaken a finger bowl meant for washing their sticky hands as a 'fancy clear soup'.
Seven per cent of those who took part in the study said they were recoiling with embarrassment when their friends have started a sing-song with other diners and a third of us have had to put up with a really drunk member of the dining party.
The most common table manners Britons have instilled in them as a child are not speaking with your mouth full, no elbows on the table and placing your knife and fork together when you have finished your meal.
But as many as 32 per cent of adults felt that some table manners seemed old fashioned now - with 39 per cent claiming it is fine to use your phone at the table provided it's just once or twice.
Nearly one in ten went as far to say that it would be virtually impossible to sit and eat a meal without using their smart phone.
A quarter said it would be acceptable to turn to your mobile if you needed to Google something from the menu and 41 per cent said it would be fine to use the calculator feature in order to work out how to split the bill.
One in five said it's perfectly okay to upload a picture of your meal to social media.
Catherine Marshall, communications director at Fourth, said: "Proper manners and a love of eating out are two things the British are well known for, but the lines between acceptable and unacceptable manners when eating out are blurring.
"Once frowned upon, getting your phone out to check texts and emails at the table or to snap pictures has become common as people embrace technology into their eating out experience."
The poll found that the average adult eats out nearly four times in a typical month and two thirds said the more you eat out the more accustomed you become to restaurant etiquette.
More than half of the adults surveyed (51 per cent) said they had been intimidated in a posh eatery in the past whether it was down to what cutlery to use, how to pronounce foreign dishes or how to behave.
A further 43 per cent said they avoid certain restaurants if they have their children with them to avoid embarrassment, while nine per cent said they never take their kids out to eat as their table manners are just too bad.
The poll found the typical Brit will leave an online review of a restaurant between three and four times a year, with 85 per cent claiming they are more likely to write a review if they have had a positive experience.
TOP 35 RESTAURANT FAUX-PAS
1. Clicking your fingers for the waiter's attention
2. Talking with your mouth full
3. Being too loud and raucous
4. Wiping hands on the tablecloth
5. Blowing your nose in a napkin
6. Letting children come and go as they please from the table
7. Licking a knife
8. Letting children listen to videos on a phone
9. Texting at the table
10. Answering / making a phone call
11. Letting your children play with cutlery and condiments
12. Touching up make-up at the table
13. Asking for a toothpick and removing food from your teeth at the table
14. Placing your phone on the table next to you
15. Not leaving a tip
16. Blowing on hot food too loudly
17. Taking a picture of your meal
18. Not sharing a 'sharing platter' and eating more than your fair share
19. Asking for ketchup / mayo in a fine dining restaurant
20. Flirting with the waiter / waitress
21. Tucking your napkin in your collar
22. Holding a knife like a pencil
23. Scooping out the ice from your drink with your fingers
24. Holding a knife and fork in the wrong hands
25. Paying your EXACT share when splitting the bill
26. Going outside to smoke
27. Pouring white wine in a glass that was being used for red
28. Downing a drink as soon as it arrives
29. Using the wrong cutlery for the course
30. Making a signing gesture for the bill
31. Moving around chairs and tables to accommodate your party
32. Ordering a fussy meal (no chips, no dressing etc)
33. Mispronouncing the name of a dish
34. Asking for a knife and fork because you can't use chopsticks
35. Asking if a meal is vegan, dairy free, gluten free etc