Arthur Sleep King Arthur King Size 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
£605
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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
- 75cm each, every night: Two sleepers get 75cm of width apiece, which means you can both change position without negotiating over the middle of the bed.
- Pocket springs reduce partner disturbance: If one of you gets up hours before the other, individually moving springs limit how much of that early alarm travels across 150cm of mattress.
- Extra length for taller sleepers: At 200cm, the UK king is 10cm longer than the UK double, which matters more than width if one of you is approaching six foot.
- Medium firm support across a wider surface: The medium firm tension keeps the surface supportive rather than sink-in, so the middle of a shared bed holds its shape over time.
- Room for the dog too: If a pet claims a corner of the bed most nights, the step up from a UK double leaves you a fair share of the space.
This size suits you if...
You share the bed every night and have started to feel cramped in a UK double, you and your partner keep different hours and want less disturbance when one of you gets up, or one of you is tall enough that the 200cm length is the real draw. Your bedroom comfortably clears our suggested minimum of 2.7m x 2.9m for a UK king.
Consider another size if...
Your room is smaller than the 2.7m x 2.9m we suggest for a UK king, or you sleep alone. The UK double would suit you better, and we suggest at least 2.6m x 2.8m for that size.
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FAQ's
How big is the King Arthur mattress in a UK king?
It measures 150 x 200cm, or 5ft x 6ft 6in. That gives two people sharing 75cm of width each. It's 15cm wider and 10cm longer than the UK double, so you gain length as well as elbow room, useful if either of you is on the taller side.
Will the King Arthur UK king stop me feeling my partner move?
Nothing removes movement entirely, but this size helps in two ways. The pocket springs respond individually rather than as one block, and 75cm of width each means you're rarely lying close enough for a turn to reach you. If your schedules differ, that combination makes early starts less intrusive.
Is the UK king King Arthur long enough for someone over six foot?
At 200cm it's 10cm longer than the UK double, and for taller sleepers that extra length is often the upgrade that matters, keeping feet on the mattress rather than hanging past the end. The UK super king is the same length, so sizing up further only buys width, not more legroom.
What room size do I need for this mattress in a UK king?
We suggest at least 2.7m x 2.9m so you can walk around the bed and open drawers without shuffling sideways. New build master bedrooms can be tighter than they first appear once wardrobes go in, so measure the floor space you'll actually have left, not the empty room.
Should I choose the King Arthur in a UK king or a UK super king?
The UK king is 30cm narrower than the UK super king; both are 200cm long. If your priority is length or reduced partner disturbance, the UK king does the job in more rooms, since we suggest at least 3m x 2.9m for the UK super king. Go bigger only if width is genuinely the issue.