Door to downstairs WC dilemma

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At the moment, there is a pantry open to the kitchen, but thinking of converting the pantry into a downstairs WC. But I do now want the door to open into the kitchen, but prefer a door coming off into the hall way. Does anyone know if it's possible to create a door out of the "wall" under the stairs as shown in the picture? It's not our house but a similar one...ours have a curved wall rather than with the edge...otherwise the same.
Is the wall holding up the stairs or is it a decorative feature?
Thanks!

No, it doesn't hold the stairs up - lots of 1930s semis where we are have the toilet effectively under the stairs like this. Ours just has a normal internal door opening into the hallway (rather than into the loo).

So it shouldn't be a problem taking out this wall and having a door against the stairs opening out to the hall way like in most houses like this? Yes this is a 1930s semi. Maybe it was created like this to have a bigger pantry.

where will the soil pipe go?

There is a soil pipe running directly down from the upstairs loo, so I'd have thought it should be easy enough to join it to that?

We're just about to put a loo under our stairs in a Victorian house and this seems quite coming. You'll need a structural engineer to advise whether there is any issue.

Is this soil pipe inside the house? How far away from the proposed WC?

the pipe will have to slope slightly downwards, so unless the soil pipe is on the other side of the wall, it may have to run under the floor. This is easier with a wooden floor over a void, than a concrete one.

It is easier to join into modern plastic than into old cast iron or underground clay pipes.

No it runs outside the house and the proposed WC will be right under the upstairs WC and I'm pretty sure it is a plastic pipe.

I guess we might be able to cut off a door shape from the wall rather than taking the whole wall off....

Sounds exactly like our house OP. Yes to soil pipe outside, toilet directly above, door shaped hole rather than removing whole wall.

Thanks namechanged Just hoping that cutting a hole is straightforward!

Our 1930s staircase looks very similar to the one in the picture and it is self supporting. We have totally removed the wall to open up the hallway.