The Navy Suit.

Navy is not a single colour. True navy — a deep, pure, slightly cool blue — is the most formal and most versatile shade. It is the choice for the suit that needs to work in a boardroom. A slightly lighter navy — closer to a mid-blue — is less severe and more relaxed in feel; it is appropriate for a range of professional contexts but less so for the most demanding formal settings. A bright or washed navy starts to read as casual.

In fabric texture, a plain-weave smooth navy worsted is the most conservative and formally correct. A subtle twill gives the cloth a slight movement in the light. A fine herringbone in navy is a classic and pleasing alternative. A navy with a thin chalk stripe adds formality and character simultaneously — the pinstripe navy is one of the most traditional professional suit combinations in the world.

Navy is the most shirt-friendly of all suit colours. White shirts read clean and formal. Blue shirts — from pale blue to mid-blue — work very well, navy on navy in varied shades being a classic of business dress. Cream or ivory shirts add warmth. Stripe shirts, Bengal stripe or fine bar stripe, work excellently with a plain navy suit.

With ties, navy is equally forgiving. Red and burgundy ties add authority. Yellow or gold ties provide contrast. Greens and mid-blues work with care. A plain navy knit tie is a classic and understatedly correct choice. For occasions where a tie is not required, a well-cut open-collar navy suit with a white or blue shirt and a pocket square is one of the most polished looks available.