German restaurants with Wurst, Kartoffelpuffer and beer will also normally generate murmurs of approval. For the culturally inclined guests, a short railway trip from Bonn to the UNESCO-listed castles in Brühl and its Max-Ernst-Museum, get another big tick too.

But there is one activity that gets a big X — in other words a big fat no — with wild horses incapable of dragging British friends anywhere near: And that would be a trip to a key icon of German culture, the winter sauna.

Why? The Brits simply do not share the love of nudity unless it is part of a naughty, sea-side post card or a smutty, late night movie.

Most are downright embarrassed if not afraid at the very thought of being seen starkers in public and, according to surveys, even in the privacy of their own homes.

For many the mutual removal of clothing is considered a pre-requisite to sex rather than a pre-condition for leisurely hours in a dry or steam bath.

In fact, such is the fear of many Brits about being seen naked in the first place — even by their wife or closest partner — most would probably prefer intimacy and intercourse during the pitch blackness of a solar eclipse or a power cut.

I have tried all the straight-forward arguments to tempt my fellow countrymen and women to a local sauna.

Like, “Look it is not about sex, you will not be an extra in a low-budget porn movie” or “Germans don’t stare, they are not interested in your wiggly bits” or “It is about health and relaxation” or “We were born naked, it is the most natural thing” and finally, with steam now percolating from my ears “nobody cares if you don’t look like Gisele Bündchen or Martin Bergmann!”.

But none of this passes the mustard: There is either outrage that one is persisting to push this crazy plan, nervous giggling or worried looks that I have somehow lost all morality since living in Germany.

Why the British are so body-obsessed and nudity-averse probably requires a longer article and some deeper psychological analysis.

But perhaps the society that gave birth to the Swinging Sixties and the Cool Britannia of the 1990s is far more inhibited than it wishes to admit.

According to an official UK Government survey from four years ago, nearly 60 per cent of Brits are totally not at ease being naked or don’t even want to talk about it-- women even more so.

The more than 100-year-old German tradition of nudism and naturism — known as the Free Body Culture (Freikörperkultur) — also has strong social and political roots.

These embrace notions of equality, freeing people from shame and escape from the unhealthy living environments in the crowded cities of early industrialization. In the former East Germany there is some suggestion it provided an anti-dote to a more authoritarian regime.

I recently read nudity at beaches, in parks and other public places in Germany is under attack and less tolerated than before perhaps linked with reunification and the influx of people from places like Britain with far more prudish views.

Soon the German sauna may be the last hold out of this very special cultural tradition — one that in many ways offers a direct and perhaps healthy challenge to the sexualization and stereotyping of the human body shape so prevalent in contemporary advertising, magazines and mainstream film.

I have to admit that it took me a while to overcome my upbringing and can thank my old friend Stefan for guiding me through the etiquette and discovering the deeper delights of the German sauna culture.

On my first visit to one — in this case in Frankfurt one winter’s night nearly ten years ago — Stefan asked me which sauna room I wanted to try.

I pointed to one on the left declaring enthusiastically “Because there are more hot chicks there!”. I was swiftly rebuked and told a visit to the sauna was nothing to do with the abundance of chicks hot or cold.

I also eventually learned not to shyly dangle my towel over my nether regions; to not turn my back nervously in the locker room; to stop chatting like a rabbit during the Aufguss and appreciate the silence, the calming swish of the towel and blast of hot air.

It may take me longer to understand why some people find it enjoyable to sit suffering like an Arctic fox for ten minutes in an ice room; splash heartily through a freezing-cold stream or gaily slap ice cubes over each other’s naked skin as the winter sun sets over the Scandinavian-style huts.

But today I have learned to enjoy the simple freedom of being nude in a room with others, feeling relaxed for the first time in my unclothed body and without worrying if it matches up to the person sweating beside me or the cover model on this week’s GQ magazine.