Why our sleep experts loved it
Note: This review is based on the mattress’s specs and design - we didn’t get to lie on it in a showroom. Think of this as a lab coat analysis rather than a sleepy-time field test. M&S tells us the 1500 Pocket Spring Extra Firm Mattress is built with 1,500 individual pocket springs that “react to your body’s contours,” plus an edge-to-edge spring layout for uniform support. A thin foam layer adds a touch of comfort, but with an extra-firm rating, don’t expect a plush hug - it’s more of a controlled embrace. The cover has anti-odour, antibacterial and anti-allergy finishes, and there are vents and sturdy side-stitching for breathability and durability. M&S backs the build with a 10-year guarantee . In short, this is engineered as an orthopaedic workhorse, not a fluffy featherbed.
Comfort and Feel If you crave a sinking, pillow-top experience, this isn’t it. The extra-firm label is literal and it feels very firm. The foam layer provides “extra comfort”, but it’s still a firm bed at heart. One owner quipped it’s “the firmest of all” mattresses they’ve tried and recommended using a topper for softness. In practical terms, your hips and shoulders won’t sink deeply into foam. That means less contouring hug and more of a stable, uniform surface. Firm fans (especially those who like sleeping on their backs or stomachs) will find it nicely supportive. But if your comfort ideal is a cloud-like sink, you may want to plan for a plush topper or to explore a different firmness.
Support and Spinal Alignment Extra-firm mattresses are designed to keep your spine straight rather than curved, which helps maintain alignment (especially on your back or stomach). M&S even notes this has an “extra-firm feel” meant for “back support” and tension relief. In fact, studies often recommend a medium-firm surface for optimal spine health, since medium firmness lets some curve while still offering support. Going firmer, as this mattress does, effectively locks your spine straighter. For many sleepers—particularly heavier or back-sleepers—this can feel solid and stabilizing. Just remember that if you’re lightweight or have a very curved body shape, you might notice more pressure under your hips or shoulders. In general, expect a very stable platform that resists sagging, keeping your back flat and supported throughout the night.
Sleep Position Suitability Side sleepers: Likely to feel the firmness. Firm mattresses often put more pressure on hips and shoulders for side sleepers. Experts note side sleepers with shoulder pressure usually need soft-to-medium cushioning to ease pressure. On this extra-firm model, side sleepers (especially lighter ones) may find those joints feel a bit pinched. A good topper could help absorb pressure, or you might prefer a softer mattress style.Back sleepers: This is where extra-firm shines. Your lower back will get strong support, and with the spine aligned, it can relieve tension. One reviewer agreed: it’s “perfect for back sufferers”, meaning people with back pain often like the firm support. If you sleep on your back, expect a very flat spinal posture that many health pros endorse.Stomach sleepers: Also a good match. Stomach (front) sleepers generally need a firm surface to prevent hip sinkage and keep the torso level. The pocket springs and foam here will keep your hips and shoulders elevated in line with your legs, which prevents the notorious lumbar arch. So if you find softer beds make your hips too low (straining your back), this extra-firm mattress should address that problem. Suitability for Different Body Types Lightweight sleepers: If you weigh less than average (say under 60kg), this mattress might feel very firm - almost like lying on a smooth hardwood board. You might barely compress the springs, so there’s minimal “give.” Some light sleepers report needing an extra layer (like a plush topper) to soften the feel. In that sense, petite sleepers should approach with caution if they want cushioning.
Average-weight sleepers: People around the middle range (60-90kg) will compress the springs a bit more and might find it just firm enough. Your body weight creates a modest sink, so you get support without extreme hardness. This mattress will feel solid and supportive, though you might still notice a distinct “edge” where the spring coil resists pressure.
Heavier sleepers: Larger individuals (90kg+) may actually find this mattress ideal. Your weight will compress the springs more deeply, creating a slightly softer feel (perhaps more like a 7/10 than a 9/10) while still keeping strong support. Extra firm beds often suit heavy sleepers because they rarely bottom out the springs. Also, the robust spring count and heavy construction (up to 57kg for a king size) handle weight well. Heavy sleepers should get a durable, supportive surface from this mattress.
Motion Isolation Because each spring is individually pocketed, movements stay relatively localized. M&S claims the springs “work independently” to reduce motion transfer. In plain terms, your partner can toss and turn without the whole mattress rippling like a waterbed. It’s not as dead-silent as thick memory foam (which virtually eliminates motion transfer), but it’s better than an old continuous coil or hybrid without isolating layers. There is also that foam layer adding a bit of damping. Many owners have noted that when their partner shifts, it’s not too disruptive—helpful if one of you wakes up easily.
Temperature Regulation and Breathability Springs inherently breathe, and this mattress has extra features to stay cool. Notably, the Ortho version mentions eight air vents around the sides to increase airflow. These vents let warm air escape from inside the mattress. The cover (likely a cotton-blend treated with odour and allergy protection) feels fairly breathable, and the fibrous fillings inside wick away moisture. There’s no fancy gel or phase-change layer here, but the nature of an open pocket-coil system means heat doesn’t get trapped. In practice, this mattress should sleep cooler than an all-foam model. If you’re a warm sleeper, you’ll still want breathable sheets, but at least the design isn’t working against you. Users have mentioned “great for back” and didn’t complain of it feeling hot, suggesting temperature isn’t a major issue.
Materials and Construction The core is the name of the game and made up from 1,500 pocket springs (for the King size; fewer springs in smaller sizes, but always a high count per square meter). Each spring is wrapped in its own fabric pocket, so it moves on its own. Above the springs lies a comfort foam layer - M&S doesn’t specify if this is memory foam or polyfoam, but at extra firm, it’s probably a high-resilience foam for slight cushioning without sink. The cover is quilted and treated to be antibacterial, anti-odour, and anti-allergy, which can benefit sensitive sleepers (though “anti-allergy” is usually a surface treatment, not a guarantee). Around the edges you get three rows of reinforced side-stitching, which helps maintain shape and prevent internal shifting. There are four handy handles (two per side) to help you lift or turn the mattress. Weights range from about 32kg for a small single up to 69kg for a 6'0" super king, so it’s solidly built. M&S even notes it’s made in the UK, reflecting local manufacturing standards. Overall, it’s a no-nonsense construction focused on support and durability.
Durability and Long-Term Use Durability looks promising here. Metal pocket springs tend to hold their shape for many years (longer than cheaper foam layers alone). The triple side-stitching and robust cover imply it’s built to last. M&S explicitly recommends flipping and rotating this mattress regularly - weekly for the first 3 months, then quarterly - which will also lengthen its life. The big hint is the 10-year guarantee: a manufacturer won’t do that if they expected it to sag in 5 years. In use, expect the springs to remain relatively springy (they’re steel, after all) and the firmness to stay consistent if you follow care instructions. Reviews (where available) show many people still calling it “excellent” on comfort and quality after months of use. In short, this mattress seems engineered to stay firm and supportive for the long haul.
Ease of Setup and Use This mattress is a setup breeze because no assembly is required . It comes fully built, wrapped in packaging, and M&S’s delivery crew will place it in your room of choice and remove the packing. No worrying about wrong screws or confusing manuals. The only slight challenge is its weight with a king size coming in at around 57kg, which is quite heavy if you try to move it yourself. Thankfully, those four handles on the sides are sturdy and designed for exactly this purpose. Once it’s in place, you just lay on your sheets. Flip/rotate instructions (every few months) are straightforward, so upkeep is low-hassle. In daily use, it’s just a flat surface - no zippers, no electric adjustments - so nothing can really “go wrong.” Users often praise the delivery and placement experience, saying it arrived as promised and the team positioned it exactly where they wanted.
Value for Money For a high-quality pocket-spring bed with 1,500 coils and a 10-year warranty, the price (£599-£799 for king size) is quite reasonable. You’re not getting a cheap no-name mattress - this is a branded M&S product with premium features. Customers seem to agree; one reviewer gave it a 5/5 for value, and overall ratings of quality and value are excellent. Considering it includes delivery and setup, and comparing to similar high-end ortho mattresses, it stands up well. In the context of mattress pricing, it occupies the mid-to-upper range, which matches its solid build. The extra-firmness is somewhat niche (so it’s not for everyone), but for what it is, the price reflects its durable construction and support technology. In short if you’re paying for genuine orthopaedic-level firmness and a decade of warranty - a decent deal if that’s what you want.
Who Is This Mattress Ideal (- or Not Ideal -) For? In summary, this mattress is a great pick if you love very firm support or need it for medical reasons. It’s ideal for back and stomach sleepers who want spine-alignment, heavier sleepers who need sturdy coils, or anyone with lower-back pain who finds softer beds too lumpy. Allergy-prone sleepers might also appreciate the treated cover. However, it’s not ideal for someone who sleeps on their side and craves plush cushioning under hips and shoulders. Petite or lighter-weight people will likely find it too hard without adding a topper. If you sleep hot but like springs, you’ll do fine, but this won’t magically cool you - it’s just less insulating than foam. Finally, if you’re not fond of the “board-like” feel, consider one of M&S’s medium or pillow-top models instead. But if your ideal mattress is firm as a board but still with a little give from 1,500 springs, this M&S Extra Firm is right in your sleep lane.
Summary: The M&S 1500 Pocket Spring Extra Firm Mattress is built to last and loves heavy-duty back support. It’s excellent for front/back sleepers and heavier people who need an orthopaedic feel. Side sleepers or anyone seeking softness should probably look elsewhere (or use a topper). In the firm-mattress world, this one stands out for its quality and warranty - just don’t expect a cloud hug unless you add your own.
Why you can trust WantMattress
We spend hours testing (and/or researching) every product or service we review, so you can be sure you’re buying the best. Find out more about
how we test .
