The suit jacket is all but redundant in a modern office. Central heating did away with the need for anything more than a shirt to keep you warm. Then air conditioning ensured the temperature would stay exactly the same, all year round. So no one wears a jacket because they need to.

Plus it’s not the easiest thing to wear if you work at a computer. Even the hacking jacket I have with a bi-swing back doesn’t make it comfortable to sit with your arms outstretched all day. Hunters have to lower their guns occasionally.

In my opinion, a waistcoat is the solution. It leaves your arms free to type at the computer for hours without restraint. You can answer the phone, wave at the tea lady and get that file from Andrew’s desk without discomfort. I have bespoke jackets with very high scyes and large sleeveheads; I often wear them with bespoke shirts that have equally high armholes; a jacket is still never as comfortable as a waistcoat.

But by far the biggest advantage of wearing a waistcoat is that it is smart. If you take any interest in your clothes, you’ll want to give them at least a decent chance of making you look good. And the waistcoat does this.

Suddenly that super-180s Loro Piana wool you carefully picked out is given true rein. Your silhouette is lengthened in much the same way as by a jacket, flattering the figure and keeping the belly tucked in. As a waistcoat is one of the hardest things to make (tight-fitting yet flexible) it shows off the skills of your tailor. It keeps your shirt in order – no matter how fitted a shirt might be, or long its tail, it will always start billowing out around the waistband after a while.

And finally, it keeps the tie in place; for me, this is the greatest pleasure. The tie knot remains prim, at attention. When worn with a waistcoat the tie is contained and supported. It is the focal point, the flash of silk in an otherwise matte outfit. It is an arch of distilled style.

What you wear over your waistcoat can then depend entirely on the weather outside: an overcoat in the winter, a jacket in the spring, nothing in the summer. It’s worth retaining the jacket, as it will always look smartest for meetings, functions and interviews. But it is no longer functionally useless.

Some people, it has to be said, don’t like waistcoats – they’ve rarely had one made bespoke. They may still consider the silk back too showy ­– then have it in a dark, complementary colour to the suit, or even from the same wool. Anything will help that makes the waistcoat feel like an external garment – a collar, for example, preferably notched. 

In my opinion a man working in an office should wear a waistcoat. It is flattering, comfortable and makes the best out of his clothes. This is the Logical Waistcoat Theory.