Firmness
Type
Pocket Spring
Depth (cm)
29
Number of Layers
4
Trial Period (nights)
100
Warranty (years)
7
Price Range
£3,499 to £6,499
Best Sleeping Position(s)
Certifications
Assessed from the specification published by Feather & Black, captured September 2026, and from regular price comparison across our UK retail partners.
Choose the Byron if you want a genuinely natural, seasonally flippable mattress with a firm feel. Seven layers of micro and Cortec pocket springs, 13,060 in total, give precise contouring, which means the surface responds to your shoulders and hips rather than pushing back as one flat slab. Wool and silk on the winter side absorb moisture and regulate temperature, so hot sleepers get help too. The Cortec springs are glueless and fully recyclable, a rare thing at any price. It comes in six sizes up to Emperor. Yes, it's expensive, but Feather & Black lists a 100-night comfort promise and a 7-year guarantee, which softens the risk a little.
Key Features & what's inside
- Top surface. Generously layered with 100% natural cashmere, mohair, cotton, hemp, flax and British wool. This is the winter side, where insulating wool with silk absorbs moisture and helps regulate temperature, which means fewer clammy nights in colder months.
- Fillings. Soft cashmere, sourced as a byproduct from the fashion industry, brings insulation and a supremely gentle surface feel. It sits alongside traceable British sheep's wool from the British Wool partnership.
- Springs. 13,060 responsive springs across seven layers of high-density micro and Cortec pocket springs, which means very precise, localised support. The Cortec system is glueless and 100% recyclable.
- Reverse surface. A breathable cotton side designed for summer use. Flip the mattress with the seasons to get the right sleeping temperature year round.
Layer details from featherandblack.com product page, September 2026.
Who's it NOT for?
This is a firm mattress, so lightweight side sleepers may find it too unyielding at the shoulder and hip. It also needs flipping seasonally, which is awkward if you struggle to turn a heavy mattress. And starting at £3,499, it's simply not the right buy if your budget sits anywhere near the mainstream.
Harrison Spinks Byron Mattress
View all mattresses
How firm is the harrison spinks byron mattress?
It's listed as firm. That suits back and front sleepers and heavier builds well, although lightweight side sleepers may find it a little too solid for comfortable pressure relief at the shoulder.
How many springs does the harrison spinks byron have?
It has 13,060 springs arranged in seven layers of high-density micro and Cortec pocket springs. The Cortec springs are glueless and 100% recyclable, and the layered design means more precise contouring than a single layer of standard pocket springs.
Does the harrison spinks byron come with a trial and guarantee?
Feather & Black lists a 100-night comfort promise and a 7-year guarantee. These are the retailer's own terms rather than Harrison Spinks manufacturer offers, so check the conditions wherever you buy.
What sizes is the harrison spinks byron available in?
Six UK sizes: Single, Small Double, Double, King, Super King and Emperor. Prices run from £3,499 to £6,499 depending on the size you choose.
Do you need to flip the harrison spinks byron mattress?
Yes. It's dual-sided, with a warmer wool and silk winter side and a breathable cotton summer side, so you flip it seasonally. Bear in mind it's a substantial 29cm-deep mattress, so turning it is easier with two people.
Couldn't find an answer to your question? Send us a message