Little Greene's Marine Blue is a rich petrol blue with real depth, and the worst thing you can do with it is treat it like a feature wall with crisp white skirting. It looks accidental that way. Drench the room instead — walls, woodwork, ceiling — so the depth reads as deliberate architecture rather than a colour you bottled out of committing to.
Once it's wrapped round the room, warm it up. Marine Blue has a cool, oceanic pull, so everything you add should pull back the other way: smoked or amber-toned oak, unlacquered brass that's allowed to age, and warm amber lighting rather than cold LEDs.
For accents and the bits you don't drench, here's what works:
- Dulux Copper Glow (LRV 30.1) — a burnished terracotta-copper that's the natural complement to petrol blue. Brilliant on a piece of furniture, a door, or picked out in soft furnishings. This is your hero accent.
- Mylands Cigar BH.20 (LRV 11.8) — a deep tobacco brown for a grounding partner if you want a second dark tone in the scheme. Cabinetry, a fireplace surround, leather-adjacent.
- Paint & Paper Library Sand I (LRV 95.4) — a near-white with a warm sandy undertone, ideal for an adjacent room or a ceiling if you don't want to go full drench overhead.
The "but what about white trim?" question: avoid bright white. It'll fight Marine Blue and make the blue look harsher and bluer than it is. If you genuinely need a softer off-white somewhere — a hallway leading off, say — Farrow & Ball All White (LRV 92) is the cleanest you should go, and even then I'd lean to the warmer Sand I against this blue.
Practical tip: order sample pots of your accent and your white and live with them against the blue in evening lamplight, not just daylight. Marine Blue comes alive under warm artificial light — that's when the scheme really sings.