How do I remove a stone staircase leading to the cellar?

I have a stone staircase going down into our cellar. It looks as though it is knitted into the walls. The walls are either side of the staircase and run perpendicular to the house.

It's a 2-up 2-down end of terrace with the staircase in the centre splitting the rooms. The ground to first floor staircase is wooden construction, the ground to cellar is stone construction.

I need it removing so a new more compact staircase can go in it's place to accommodate a lower floor with a cellar conversion. I am particularly worried about what structural benefits this staircase is giving to the walls...

How do you go about removing these?

The first thing that came into my head was an angle grinder with a decent disc and slice them off at the wall - leaving the knitted section embedded in the brickwork.

Thanks.

I would proceed with utmost caution. There could even be some cantilevering support being given by the staircase, or it providing some bracing to the wall. If you remove it, even without disturbing any stones in the wall, you could end up wearing your house.

Generally I'm quite gung-ho, but in this situation I might be calling on a structural engineer to make sure.

Yeah that's exactly my approach normally. The walls themselves have very little lateral support, other than being knit into the main side walls of the house and one small internal lateral wall. The stone work is just sheet stone from one wall to the other, so other than the mortar providing the join, there is no actual bracing.

I hazard a guess it is likely safe, but only if done carefully. Unfortunately masonry doesn't like vibration damage, hence my thought about using the angle grinder nice and carefully.

I think I'll bite the bullet and get a structural engineer visit, got some other stuff he can look at anyway.

I've the same sort of staircase in a similar house and before I looked I was just going to rip it out, thinking it was a normal staircase but now it is going to stay and we'll work around it.

Working around it was Plan A, but unfortunately there isn't enough head-height and space to accommodate the current pitch - now on Plan B

Lowering the floor forces a requirement of a slightly steeper staircase.

Looks like it's not a job I can do myself with any confidence. We are getting specialists in for the cellar foundations at some point, I might ask them what they think and if they can cut it out.