Try to ignore the plane. How high are those trousers?

OK, it’s a fair cop.

Someone commented to me recently that I wasn’t living by my waistcoat theory (see post on January 15) and they’re right. I don’t pursue it every day by any means but I still believe in its internal logic, and the clothing combination it suggests is certainly something I make use of regularly. I just like a little variety.

The waistcoat theory suggested that modern air conditioning meant a waistcoat and trousers would be the work attire most in line with traditional menswear. As men never wear a jacket around the office, the beneficial effects of a suit are almost entirely lost. A waistcoat, on the other hand, retains the shape and elongation of a suit while being comfortable for work at a computer and not too warm for an office with central heating.

This was meant as a theory more than anything else – to make a point about how a suit, despite all the time people spend thinking about it or having it made, is actually worn. But it wouldn’t be much of a theory if it was never put tried in practice.

So today I opted for a grey flannel waistcoat and trousers (two pieces from a three-piece Ralph Lauren suit), dark brown derby shoes from Richard James, and blue shirt and dark blue tie.

One tip: both waistcoat and tie should be plain. Most people have memories of an awful waistcoat some relation or other wore to a Christmas lunch. This is not a wedding and the waistcoat should not be fancy. The tie, equally, should not be aimed at drawing attention to itself. If anything the shirt should have the pattern, perhaps a thin stripe, which will also help add width that the waistcoat lacks compared to a jacket.

There is one problem with the theory though – most waistcoats are made too short. Originally, all suit trousers sat on a man’s waist (above the hip bones and probably just under the belly button). At this height, the waistcoat and trousers would overlap by at least an inch or so, allowing a man to sit down or stretch without exposing his shirt.

Today, most waistcoats are made at the same length, but trousers are worn closer to the hips. This can create unattractive ballooning out from the waist of the trousers, particularly if the shirt is not particularly fitted.

Some waistcoats are made slightly longer in recognition of this. And while they will never completely correct the problem – as they would have to go down over your bum to overlap the trousers by an inch or more – this is a step in the right direction. I recommend Flight, a company that sells high-quality suit separates in green, blue and grey flannel.

An alternative, for those brave enough to go down this route, is to wear braces with your trousers. Buy trousers with a decent rise and hitch them up under the waistcoat with the braces – a belt won’t work, it doesn’t keep the waistband secure enough and will create a bulge under the waistcoat.