Arthur Sleep King Arthur Single 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
£449
Get the lowest price we've found
Save with the previous model
Some retailers still sell the earlier version of this mattress for less than the current model's best price.
Arthur Sleep King Arthur Mattress
More available sizes
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
- Fits a child's room with space to spare: At 90cm wide, the UK single leaves room for a wardrobe, desk and toy storage in a bedroom that has to do several jobs at once.
- Medium firm support for growing sleepers: The medium firm tension resists slumping, which means good spinal alignment for children and teens as they grow.
- Works for two beds in one room: Siblings sharing, or a guest room set up with twin beds, can fit two UK singles plus a walkway where one larger mattress would dominate.
- Sensible for spare rooms doubling as offices: A UK single takes up the least floor space of any adult size, so a study can host occasional guests without giving up the desk.
- Cheap, easy bedding: Single sheets and duvets are the most widely stocked of any size, which keeps running costs down for a child's or guest bed.
This size suits you if...
You're buying for a child's or teenager's room where the bed shares space with a desk and storage, you're furnishing a spare room or study that needs to sleep occasional guests, or you're a single adult in a compact room, perhaps a first flat or a loft conversion where only a narrow footprint fits under the slope.
Consider another size if...
You're an adult who spreads out at night, or you sometimes share the bed. The UK small double of this mattress gives you 30cm more width at the same length; we suggest at least 2.4m x 2.8m of floor space for it.
Similar Mattresses in This Price Range
Did you know? On Mattress Unboxed we have over 1,000 different mattresses to suit all types of sleepers. View all mattresses.
FAQ's
What size is the Arthur Sleep King Arthur UK single?
It measures 90 x 190cm, which is 3ft x 6ft 3in. That's the standard UK one-person size, so it fits ordinary single bed frames, and standard single sheets and a 135 x 200cm single duvet fit it. We suggest allowing at least 2.1m x 2.8m of floor space in the room.
Is the King Arthur UK single suitable for a bunk or mid sleeper frame?
The width matches standard bunk and mid sleeper frames, which take a 90 x 190cm mattress. Raised frames also have a maximum safe mattress depth, and Arthur Sleep doesn't publish a depth for this model, so check the brand's own guidance against your frame's limit before buying.
Is a UK single King Arthur firm enough for a growing child?
The medium firm tension is a sensible choice for children and teens: enough resistance to keep the spine aligned as they grow, without feeling like a board. The pocket springs adjust to a lighter body individually, so a smaller sleeper still gets contact and support rather than lying on top of an unyielding surface.
How much bigger is a UK double than this single?
The UK double is 45cm wider than the UK single and the same length, at 135 x 190cm. If you're weighing the two, the deciding factor is usually the room: we suggest at least 2.6m x 2.8m of floor space for the UK double, against 2.1m x 2.8m for the UK single.
Where can I buy the King Arthur mattress in a UK single?
The prices shown on this page come from the retailers currently listing the UK single, and they're updated as retailers change them, so compare the live table here rather than relying on a figure you saw elsewhere. Availability can differ between sizes, so what's true for the UK double may not apply to this one.