This is the front. But the biggest difference is on the back

There are many ways to try and judge the quality of a ready-to-wear suit. The most obvious is the use of a floating canvas (padding in the chest that is sewn loosely in rather than glued to the front of the suit). But apparently Matalan is now offering suits with floating (though half) canvas for under £100.

Another way to judge the quality of a suit is the cloth. But this is largely a matter of taste. Very cheap fabrics always look cheap, but the difference between a mid-range wool and expensive wool is often small differences in the finishing, the presence of cashmere, or a higher super-100s number. And the last, while definitely more expensive to make, is not necessarily better. It’s just thinner.

Perhaps a better way to judge quality is to look at what parts of the suit have been finished by hand. I would suggest you look in four places for this.

The first is probably the easiest: handsewn buttonholes. While these are entirely for display – they serve no greater function than machine-made buttonholes – they are more attractive and sought after.

The slightness of the difference, however, can be judged by how you spot them: you look at the back. The rear of the buttonhole, on the inside of your jacket, cuff or lapel, betrays handwork. While both hand and machine-made buttonholes may appear very tight and regular on the outside, the rear of a hand-sewn hole is far more irregular and erratic. It’s extremely difficult to get both sides perfect by hand.

That’s one thing to check. The second is more functional. Open up the jacket and look at the edge of the sleeve lining, where it meets the body lining of the jacket. Sleeves and their linings will often be put in by hand on well-made suits because it is far more difficult to sew around in a circle, and to ease in the extra fullness of the sleeve into a smaller armhole.

Hand stitches should be easy to spot here. Just look at a series of three or four of them. Are they all of the same size and distance apart? If not, they’ve been sewn by hand.

Next, turn up the collar and look for similar stitches where it is joined to the back of the jacket. For similar curvature reasons, and questions of style, that seam is often sewn by hand on good suits. It makes the collar lie flatter and more evenly all the way around. The stitches here may well be in a darker thread and more camouflaged against the cloth, so they do not stand out if a gentleman decides to wear his collar popped. But look closely and you should see them.

Last, open the jacket and look at where the lining is attached to the cloth around the bottom edge. The lining will likely be folded over to disguise this seam, so you will have to lift that fold up. Handwork here is good as it allows greater movement in the lining, so you can shift your back without necessarily moving the outside of the jacket – that stays nice and sharp.

But there is also an in-between stitch to watch out for on this seam. Some jackets will have a loose but very regular stitch of two lines of thread along the bottom – Ralph Lauren suits often have this. While it is done by a machine, the effect is similar to handwork in that it allows greater movement.

Now go get some odd looks from sales assistants.