A snug is the room to be brave. It's small, it's for evenings, and it's where you actually want the walls to hug you — so forget pale and airy. The whole point is enveloping, and that means going dark, warm and full-bodied.
My top pick is Farrow & Ball Inchyra Blue — a moody blue-green-grey that reads almost teal in lamplight and looks completely different (and gorgeous) by day. It's the modern classic for a reason. If you want something greener and even cosier, Studio Green (F&B) is nearly black in the evening and stunning behind a fire or a stack of books.
For warmth over coolness, go to the reds and browns. Farrow & Ball Mahogany or Farrow & Ball Mahogany give you that rich, leather-armchair depth. A proper aged red like Eating Room Red or Picture Gallery Red (both F&B) is sensational in a snug lit by lamps — it glows. If you want it softer and more contemporary, Little Greene Hicks' Blue or a deep Hague Blue (F&B) both work a treat.
"But won't a dark colour make a small room feel even smaller?" Honestly — no, not in a snug. Small + dark = intimate, not claustrophobic, *as long as it's an evening room*. The trick is to lean in: paint the ceiling and woodwork the same colour (or a close tone) so the walls don't stop abruptly. That blurs the boundaries and the room reads as one cosy shell rather than a box.
Finish matters. Use an estate emulsion or modern matt on walls so the colour stays deep and velvety, and avoid anything too sheeny that'll bounce light around and break the spell.
Practical advice: get a couple of sample pots, paint big A2 lining-paper sheets, and — crucially — judge them at night under your actual lamps, not in daylight. A snug lives after dark, so that's the only test that counts. Soft, warm bulbs (around 2700K) will make all these colours sing.