Firmness
Medium Firm
Type
Pocket Spring
Depth (cm)
28
Number of Layers
5
Trial Period (nights)
100
Warranty (years)
10
Price Range
£504 to £1,024
Best Sleeping Position(s)
Certifications
Assessed from the specification published by Mattress Online, captured September 2026, and from regular price comparison across our UK retail partners.
This mattress makes sense if you want natural fillings rather than foam. The wool and cotton layers help regulate temperature, which means if you're a hot sleeper you should stay noticeably cooler than on memory foam. The 4000-spring ErgoZone 7 support system varies its firmness across seven zones, so heavier areas like your hips get more resistance while shoulders sink in a little more. Reinforced edges with metal rods and butterfly clips mean you can sit or sleep near the side without feeling like you'll roll off. It's hand-tufted, so expect a slightly dimpled, traditional surface rather than a smooth top. Six sizes are available, from UK Single up to Super King, plus an EU King.
Key Features & what's inside
- Cover. A soft-touch cotton-viscose fabric infused with M-Pure, a 100% natural, plant-based treatment. It's naturally fire resistant, which means no added chemical fire retardants in the cover.
- Comfort fillings. Luxury Hampshire fleece wool blended with layers of English cotton, traditionally hand-tufted. Wool and cotton breathe well, so this layer helps keep you at a steadier temperature through the night.
- Mini pocket springs. Small, individually cased springs sit near the surface to add comfort and soothing pressure relief. They respond to your shape more precisely than fillings alone would.
- Pocket spring support system. 4000 pocket springs zoned in 7 areas, an arrangement Millbrook calls ErgoZone 7. Each spring is individually encased and adapts to your movement, which means support that follows your body rather than the whole bed dipping.
- Edge support. Metal rods sit above and below the spring unit, held in place with butterfly clips. This reinforces the edges, so you can use the full width of the mattress without the sides sagging.
Layer details from mattressonline.co.uk product page, September 2026.
Who's it NOT for?
If you like a soft, cushioned surface you sink into, this medium to firm feel will likely be too solid, and some owners report it feels firmer still. It's also a heavy mattress to move, so if you'll be rotating it alone regularly, be prepared, though the turning handles help.
Millbrook Wool Luxury 4000 Pocket Mattress
Across 864 reviews on the Mattress Online product page, scoring 4.7 overall, owners report comfortable sleep, relief from back and neck pain, and appreciation for the material quality. Some find it firmer than expected and heavy to move, though the turning handles are valued.
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How firm is the Millbrook Wool Luxury 4000?
It's described as medium to firm. That suits most back and front sleepers, although some owner reviews mention it feels firmer than a typical medium firm, so lightweight side sleepers may find it a little too solid at the shoulders and hips.
Does the Millbrook Wool Luxury 4000 come with a trial?
Mattress Online, the retailer listing this mattress, offers a 100-night trial. That trial is the retailer's own policy rather than a Millbrook guarantee, so if you buy elsewhere, check that seller's terms before ordering.
What is the Millbrook Wool Luxury 4000 made of?
Natural fillings of Hampshire fleece wool and English cotton sit over mini pocket springs and a 4000-spring zoned support unit. The cover is a cotton-viscose fabric with M-Pure, a plant-based, naturally fire-resistant treatment. It's handcrafted in the UK and hand-tufted in the traditional way.
How deep is the Millbrook Wool Luxury 4000 mattress?
It's 28cm deep. That's a generous depth, so check your fitted sheets will stretch to accommodate it, particularly if you're moving up from a slimmer mattress.
Is there a guarantee on the Millbrook Wool Luxury 4000?
Mattress Online lists a 10-year guarantee with this mattress. As that figure comes from the retailer's listing rather than Millbrook's own site, it's sensible to confirm the guarantee terms with whichever retailer you buy from.
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