Everything you need to know about the versatile pants.

We like wool when it comes to trousers, but because we’re always opposed to wooly thinking, we’ve come up with a guide to the best ways to wear the various different weaves and colours that are available. Trousers made from sheep’s hair can be sophisticated and formal, or rustic and casual. They can convey a sense of timely relevance or a more classic approach to dressing. The choice is always personal, but it’s worth understanding the context. Why are flannel trousers best worn during the day? What is it about mohair that makes it a good choice for business travel? Are these trousers all equally formal? Wool trousers are smarter than jeans, but other than that few generalisations can safely be made. Some work best with sneakers and a shirt, others with brown suede shoes and a sports jacket. And others still are best at night, perhaps with a velvet blazer. Whatever the occasion, there’s an appropriate pair of wool trousers to match. Read on for our guide explaining the different variations, and what to wear them with.

Grey flannel is a classic element in the masculine wardrobe, and in pale shades of grey it’s also a vital part of a contemporary tailored wardrobe. The cloth has a pleasingly fuzzy appearance but doesn’t reflect any light, so it appears dull in the evening. As such, it’s best worn during the day. Despite its classic status, flannel looks entirely contemporary worn with a white shirt, a lightweight navy-coloured knit and simple white sneakers.

Rustic isn’t a word usually associated with the slick Italian tailoring brand Canali, but this flecked fabric is in essence a refined version of Donegal, a wonderful slubby weave traditionally made in Ireland and used for classic countrywear. Of course, this silk/wool mix is a luxurious version of Donegal, but the weave is textured enough to give the trousers a casual feel. Embrace the cosiness with a chunky rollneck sweater.

The legendary designer Mr Raf Simons has used virgin wool for these black trousers, which means that the wool came from lambs shorn for the first time. The result is noted for its ability to take a dye, in this case an intense black that produces a look that’s formal, architectural and modern. Accentuate the formality with a white shirt, or adopt a more creative image with a graphic tee.

Mohair comes from Angora goats, and when people talk about mohair fabric they mean wool with a modest proportion of mohair (in this case 25 per cent). The mohair imparts a slight sheen, making it a great fabric to wear at night, and it has a crispness that allows the trousers to hold a crease, which is useful if you’re travelling. These qualities make it almost the opposite of flannel. This pair of twill trousers has an unusual satin strip down the outside of each leg (see the MR PORTER guide to wearing side-striped trousers, here), which makes them most appropriate for parties or evening events.

The German label Jil Sander is known for the purity of its design vision. It makes starkly elegant clothes and these sleek gabardine trousers are no exception. Made from dark navy fabric they have a subtle diagonal weave that gives them enough texture to work without a jacket. Hard-wearing gabardine (a smooth, twill-woven cloth) was once considered to be a performance fabric, and was worn as sportswear in the days before artificial fibres began to dominate outdoor gear.