We’d all like to be happy. We put a lot of work into it. We buy self-help books, go to therapy, we buy stuff that we think might make us feel good. But we often forget a simple and inexpensive route to a certain sort of temporary happiness. Yes, friends, it’s cheap, it’s easy, it’s quick, and it’s got that medieval vibe. It’s time to be merry.

Now, what I like about the idea of being merry is that, unlike happiness, it is well within reach. It is not an abstract goal that we hope to achieve at some point in the future. You can make a decision to be merry right here, right now. All you need is friends, neighbours, family, booze and food. Just get the corkscrew and get on with it.

It’s an idea that has come down to us from the Middle Ages, when the word “merry” was used all the time. Indeed, there was a duty to be merry almost written into the ethical codes of the age, and Christmas lasted a full 12 days, during which time you were not allowed to do any work. That’s 12 days for doing nothing whatsoever, except eating pigs and geese, drinking red wine, dancing, singing and playing the lute. It is this spirit of fun that is embodied in the jovial figure of Father Christmas, and it’s this embracing of pleasure we remember in the phrase “Merry Christmas”.

But why was it so important for the medievals to be merry when us modern types sometimes forget? The medieval man and woman valued community rather than individualism, and considered that having a good time led to the smooth functioning of the village or town. Professor Ronald Hutton of Bristol University, an expert on this period of British history, says: “The medieval emphasis on community meant that there was a need to cultivate virtues that improved communal life. Merriment, which we would today call conviviality, was one of these.”

It’s that fun-loving communal spirit that Christmas really represents. Christmas is one of the last vestiges of the old-fashioned festive culture. This pleasure-seeking, live-for-the-moment attitude to life is also summed up in the words “Eat, drink and be merry, for tomorrow we may die” — a notion that actually appears first in the Old Testament. We have a responsibility to enjoy life.

There was a blip, though — it can’t be denied. Despite such an excellent medieval start, in the mid-1600s, those Gordon Browns of their day, the dastardly Puritans, methodically attacked every activity in the country that looked like it was remotely enjoyable. The maypoles were torn down, the theatres closed, music and dancing banned, the old festivals cancelled. And finally, they cancelled Christmas. Yes, friends, the Scrooge-like Puritans did actually ban Christmas because it got in the way of the serious business of working and making money. For 15 years, from 1645 to 1660, Christmas was officially illegal.

This miserable attack on fun did not, however, stop the pluckiest and most bloody-minded Brits from continuing to celebrate it. Even though the Puritans locked up the churches at Christmas to prevent services from taking place, some groups of rebels held them in private. And some were busted: Hutton says that the Puritans burst into people’s houses on anti-Christmas raids. “But they couldn’t stop the merry-making,” adds Hutton.

It was this, I believe, that gave British merry-making its edge over that of other nationalities. In this country, it is not only a social duty, promoting cohesion and common values, it is actually a rebellious act — and all the more delicious for it. Those who do make merry on regular occasions do it with a special twinkle in their eye.

And this Christmas, that means we need to tell our bosses that we’ll be back on January 8 for work and not a day before. Rather than spending a lot of money in Selfridges, we should have a lot of fun. And instead of the search for happiness, we should spread merry cheer all around. In the face of overwhelming consumerism and a decidedly un-fun-friendly government, it is your revolutionary task to have a very merry Christmas.

Tom Hodgkinson is the editor of The Idler and author of How to Be Free (Hamish Hamilton £14.99)

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