Alpha Delta Premium King Size Mattress
The Alpha Delta Premium is a hybrid mattress, meaning it combines pocket springs with foam comfort layers, with a medium firm feel.
- Minimises partner disturbance
- Stable edges, no roll-off feeling
- Soft antibacterial knitted cover
£334
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Alpha Delta Premium Mattress
More available sizes
Last seen for £278 at Mattress Online on 25th June 2026
Mattress details
Mattress
Alpha Delta Premium Mattress
Size
Firmness
Medium Firm
Construction
Foam
Pocket Spring
Hybrid
Depth (cm)
Layers
6
Layer Details
Premium Knitted Fabric
A knitted cover with antibacterial and skin-sensitive soft properties. It is the surface you actually touch, so the soft finish matters more than it sounds.
Thermobond Fiber
A thermobond fibre layer sits beneath the cover. It adds a padded feel between you and the foam below.
Two Comfort Foam Layers
Double layers of comfort foam in the quilt plus a high density, durable soft foam layer. This is where the cushioning comes from, with the denser foam helping the surface last.
Pocket Coils Spring
Springs sit in separate bags, which means each one moves independently. Alpha says this lets couples sleep without feeling much of each other's movement.
Foam Encasement
A foam border wraps the spring unit. This supports the edges, so you can use more of the mattress surface without a roll-off feeling.
Felt
A felt base layer finishes the build. It gives the springs a stable foundation to work against.
Layer details from alphabeddingco.com product page, September 2026.
Key benefits
- 75cm each for two sharing: That's 15cm more width than a UK double provides, which means fewer accidental elbows and less negotiating over the middle of the bed.
- Pocket springs across a wider bed: Each spring moves independently, so if one of you leaves hours before the other, the early alarm ripples less across 150cm of mattress.
- 200cm of length for taller sleepers: The UK king is 10cm longer than a UK double, which anyone approaching six foot will feel at their feet every night.
- Foam encasement makes the width usable: An edge-supporting foam border means you can sleep right to the sides, so the full 150cm is genuinely yours rather than a wedge in the middle.
- Medium firm feel that suits sharing: A medium firm rating tends to work for two people with different sleeping positions, though anyone wanting a soft, sinking feel should look at another mattress.
This size suits you if...
You share the bed every night and a UK double has started to feel cramped, especially if one of you keeps different hours and the other wants to sleep through the early start. It's also the size to pick if either of you is nearing six foot, since the 200cm length stops feet hanging off the end.
Consider another size if...
Your bedroom can't take a 150 x 200cm bed comfortably, or you sleep alone and don't need the width. Alpha only lists this mattress in a UK king, so if you need a smaller size you'll have to choose a different mattress.
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FAQ's
What are the dimensions of the Alpha Delta Premium in UK king?
It measures 150 x 200cm, or 5ft x 6ft 6in. That gives two people sharing 75cm of width each. The UK king is 15cm wider and 10cm longer than a UK double, a difference you notice most if one of you is tall or you've been sharing a double for years.
Will the Alpha Delta Premium UK king fit in my bedroom?
We suggest a room of at least 2.7m x 2.9m, with 3.2m x 3.2m more comfortable. New build master bedrooms can be tighter than they look once fitted wardrobes go in, so measure the clear floor space rather than the room itself, and check you can still walk around both sides of the bed.
Is a UK king good for couples on different schedules?
It helps on two fronts. The 75cm of width each means you're less likely to be touching in the first place, and the pocket springs move independently, so one person getting up at five is less likely to wake the other. The foam encased edges also make quiet exits easier from the side of the bed.
Is the Alpha Delta Premium long enough for tall sleepers?
In this UK king size it runs 200cm long, which is 10cm more than a UK double. If one of you is over six foot, that extra length is often the real reason to size up, arguably more than the width. Feet stop hanging over the end, which changes how the whole bed feels.
Can I get the Alpha Delta Premium in a size other than UK king?
No, Alpha currently lists this mattress in UK king only. If a 150 x 200cm bed suits your room and you share it, that's no drawback. If you need a UK double or smaller, you'll need a different mattress. Compare the retailers listed on this page for current UK king availability.