Arthur Sleep King Arthur Small Double Mattress
The King Arthur from Arthur Sleep is a pocket spring mattress in a medium firm tension, which means springs that respond to your body individually rather than as one block, with a supportive rather than sink-in feel.
- Medium-firm for side & back sleepers
- Minimises partner disturbance
- Support follows your body's shape
£565
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Arthur Sleep King Arthur Mattress
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Mattress details
Mattress
Arthur Sleep King Arthur Mattress
Size
Firmness
Medium Firm
Construction
Pocket Spring
Depth (cm)
Layers
3
Layer Details
Memory foam comfort layer
A 20mm layer of memory foam sits in the comfort layer, as specified by the brand. It adds a little cushioning over the springs beneath, so the surface has some give without feeling like a deep foam hug.
Mini pocket springs
An additional layer of 1200 mini springs sits within the top of the mattress. Smaller springs can respond more closely to your body's shape, so they add finer contouring over the main spring unit below.
Base pocket springs
800 pocket springs form the base of the mattress. Each spring moves independently, which gives the underlying support and helps limit how much you feel a partner moving.
Layer details from mattressman.co.uk and arthursleep.co.uk product pages, October 2026.
Key benefits
- Real room for one: At 30cm wider than the UK single, it gives a solo sleeper genuine space to spread out without stepping up to a double frame.
- Fits compact bedrooms: It's 15cm narrower than the UK double, which can be the difference between a door that clears the bed and one that doesn't in a box room or studio.
- Springs that suit sharing occasionally: Pocket springs move independently, so on the odd night two of you share, one person turning over disturbs the other less.
- Standard 4ft bedding: The small double is a standard UK size, so fitted sheets and frames are easy to find, and a standard double duvet works on top.
- Sensible room fit: We suggest a room of at least 2.4m x 2.8m, which leaves walking space where a wider mattress would leave a squeeze.
This size suits you if...
You sleep alone most nights and want more stretching room than a UK single allows, or you're furnishing a compact second bedroom, loft conversion or holiday let where a full double would crowd the room. It also suits a guest room that hosts the occasional couple rather than two people every night.
Consider another size if...
Two of you will sleep on it every night, or your room comfortably takes a wider bed. We'd recommend the UK double instead, which is 15cm wider; allow at least 2.6m x 2.8m for it.
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FAQ's
Is the King Arthur small double big enough for a couple?
For occasional nights, yes. The pocket springs respond to each body separately, which helps two people share without every movement travelling across the bed. For nightly couple use, though, 120cm of width is a squeeze, and we'd point you to the UK double, which is 15cm wider.
What room size do I need for the King Arthur in a small double?
We suggest a room of at least 2.4m x 2.8m. That's our own guidance rather than the manufacturer's, and it allows for opening drawers and walking round the bed. If your room is tighter than that, a UK single, which is 30cm narrower, may be the more comfortable fit.
Should I choose the King Arthur in a small double or a double?
It comes down to your room and who's sleeping there. The UK small double is 15cm narrower than the UK double and the same length, so it fits rooms a double would overwhelm. Sleeping solo in a compact room, take the small double; sharing nightly, size up.
Is a small double long enough for a tall sleeper?
The UK small double is 190cm long, or 6ft 3in. That suits most adults, but if you're very tall, the UK king is 10cm longer as well as 30cm wider; we suggest a room of at least 2.7m x 2.9m for that size.
Does the small double feel different from the larger sizes?
The medium firm tension and pocket spring construction are the same in every size, so the feel underneath you doesn't change. What changes is space: the UK small double gives one adult plenty, while the UK double and UK king are built around two people sharing every night.