I’m sitting across a café table from a young man with a sheaf of drawings that have an archive look to them but are in fact brand new. His Jacob Rees-Mogg attire — well-cut chalk-stripe suit and immaculate tie — sets him apart from the others in the room, who are mostly architects and architectural fellow travellers like me. We don’t dress like that. But George Saumarez Smith is indeed an architect, a very good one. He just happens to be a trad. A traditionalist, mostly a classicist. And now is very much the time of the architectural trads. They have crept up on us. There’s a revival going on, and I’m very happy about that.

George, who I’ve known for a good few years, was giving me a preview of a new exhibition of his work at the RIBA, the HQ of British architecture. It’s fair to say that the RIBA (full disclosure: I edit its magazine) has, by and large, been a bastion of modernism since the 1950s. Mainstream architects have tended to be a bit ambivalent about the trads, sometimes to the point of hostility. There are various reasons for this. One is that it is a style or approach beloved of Prince Charles, and Prince Charles is for ever associated with his ferocious 1980s attacks on modernist architecture, and subsequent manoeuvrings against big modernist projects. Another is classicism’s unfortunate association with totalitarianism. Hitler and Stalin famously loved this stuff, and to this day there’s a dark corner on social media where a thin, poisonous trickle of neo-Nazism still oozes through the discourse on traditionalist architecture, especially in Germany and America. And, finally, modernism was meant by its early disciples to be the logical conclusion, the end of architectural history. If you accept that, then what on earth is this new throwback stuff.

But the trads didn’t get the memo about modernism. They never went away. Trad buildings, from country houses via cod-Georgian and Regency spec housing estates to office blocks, never stopped being built. They became unfashionable, but they always had a market. That market — another criticism — is generally well-heeled. A classical pile is still an undoubted signifier of wealth and privilege and a good handful of surprisingly large firms of architects are kept busy by the demand for it. But it is also very adaptable — it can work at any scale. Traditionalism also includes the very different arts and crafts approach — arguably the only architectural style other than high-tech to have originated in Britain, and one that is above all domestic.

More important than style, however, is how a new estate or village, say, is laid out. You have to get the roads right, the corners and junctions, the sightlines or lack of them, the pavements or shared surfaces. To achieve hugger-mugger compactness, you don’t give in to philistine highway engineers obsessed by cars and cul-de-sacs. And in my experience the trads can be better at such fine-grain planning than some of their modernist brethren.

The influence of the old ways in architecture is proving surprisingly pervasive. Saumarez Smith’s exhibition accompanies a larger show at the RIBA by the artist Pablo Bronstein, in which he celebrates, with a certain affection, this below-the-radar style — ranging from excellent to shockingly bad — that is so peculiarly English.

Head for Soane’s Museum (now open on Sundays), that repository of the best of progressive Georgian architecture, and you will find The Roman Singularity, a show of contemporary ceramic designs in vivid colours by the young architect-designer Adam Nathaniel Furman, a former Rome Scholar. Furman — who runs a clean-as-a-whistle ‘Classicism in Modernity’ Facebook forum partly in response to the bigoted stuff festering elsewhere — has an encyclopaedic knowledge of the subject. In Soane’s famous house of archaeological clutter, Furman provides yet more with his 3D-printed ceramic mini-buildings, each a personality. This is trad with a zing.

Architecture is now at the most pluralistic point I have ever known it. A huge variety of styles and approaches is available. But formulaic designs continue to be trotted out, as far too many of the new urban rash of apartment blocks and towers in our cities bear witness. Monocultures are never good. A healthy dash of new traditionalism for the many, not the few? It’s all about architectural biodiversity. Let’s be seeing it.