Old fashioned manners such as 'ladies first', saying 'please' and 'thank you' and keeping elbows off the table are all in danger of dying out.
Never using swear words is a rule many of us struggle to stick to, along with holding doors open for the person behind you and not using your phone at the dinner table.
It also emerged more than two thirds of the population believe British society is becoming less civilised than it once was.
And one third believe politeness has become a less important part of society in recent years.
The study, commissioned by Sky Atlantic ahead of the launch of its new series Britannia, which follows an invading Roman army trying to crush the rebellious and uncivilised heart of Great Britain.
More than half of those surveyed think the notion of 'ladies first' is on the way out, and 47 per cent think nothing of using their phone at the table.
Just under half are happy to drop saying 'please' and 'thank you' and think swearing in general conversation has become more common.
Manners we still do our best to abide by are to always knock before entering a room and offering tea to guests as soon as they arrive - but even these are not followed by all.
A handshake when meeting someone new is seen as an optional extra rather than an essential and polite greeting by more than a third of people.
And a third wouldn't bother with a friendly 'excuse me' if they wanted to get somebody's attention.
Almost half can envisage a future where people refuse to hold doors open for one another, or give up their seat on public transport for those who need it more.
As for common courtesies we can't wait to fall out of use, one in five are sick of having to kiss new acquaintances on the cheek when they meet.
One in eight wish they weren't expected to tip in restaurants.
A third are convinced there are greater benefits to being rude and breaking the rules of social etiquette.
And two in five think we are too uptight as a nation when it comes to our manners.
But 11 per cent look forward to a time when they don't have to make so much effort to be polite, and 13 per cent think being rude is important so people know what you really think about them.
Almost one in 10 even believe being uncivilised to others means you get what you want more often and faster than if you minded your Ps and Qs.
But these social indiscretions do not go unpunished.
Such a shame
One in four Brits feel they have been publicly shamed by others in the past for not following basic manners or etiquette, and one in six have been told to 'mind your manners'.
The research also revealed the manners we stick to most staunchly, even as politeness in society becomes less common.
Two thirds still see the importance of covering their nose and mouth when they sneeze or cough, and 53 per cent stand by the British system of queuing - standing single file while grumbling complaints under their breath.
In fact, seven in 10 Brits see pushing ahead in a queue as the pinnacle of rudeness, along with talking with your mouth full and refusing to apologise after doing something wrong.
And 71 per cent of those surveyed wish people would pay more attention to their manners and social etiquette.
A spokesperson for Sky Atlantic, said: "I'm sure many have already noticed standards slipping, with our society becoming a little lax on etiquette expectations.
"However, will we also see a resurgence of Britannia's anarchic spirit?"
TOP MANNERS WE THINK ARE DYING OUT: 1. Not using your phone when at the table2. 'Ladies first'3. Never swearing4. Saying 'please' and 'thank you' when requesting something5. Keeping elbows off the table when eating a meal6. Giving up your seat on public transport to someone who may need it more than you7. Holding the door open for people who may be behind you8. Waiting for your host to seat you at a meal9. Shaking hands when you greet someone10. Covering your mouth and nose when you cough or sneeze11. Saying 'sorry', even for minor things12. Chewing with your mouth closed13. Waiting for everyone to be served their meal before you start eating14. Saying excuse me to get someone's attention15. Taking your place in a queue without pushing in16. Knocking on closed doors before you enter17. Holding your knife and fork in what is deemed the 'correct' way18. Queuing in single file when waiting in a line19. Making eye contact when you greet someone20. Placing the cutlery in the middle of your plate when you have finished eating