Crack in chimney wall - advice please!

[ashfp]

I recently noticed a crack in a wall which is under our chimney stack. I can't tell if this wall is supposed to be supporting the stack or not, but right now it isn't. The wall sits on a wooden lintel which half rests on the brick for the stack and the other half across ceiling joists (I think some of these bear down on the brick chimney breast below, but not entirely sure). The "supporting" wall has not been bonded into the stack, and has come away from the stack nearly all the way up. The chimney breast below still remains in place (the fireplace is blocked up, so isn't visible).
I can see no signs of movement/cracking in the stack. And I'm not sure what's caused the movement, it doesn't look like anything has moved in terms of the wooden lintel.

We live in an upper maisonette (tyneside flat), so the flat is probably getting on for 100yrs old, but I'm not sure if this wall is original.

I have uploaded a video of the chimney in more detail here:

Any advice appreciated on whether I should have the wall rebuild, removed or further support added?

Many thanks

 

[cdbe]

That looks quite dangerous to me, almost as if there was originally a second chimney breast or maybe an internal wall on the left hand side that has been removed.

 

[ashfp]

I wondered that also, but it doesn't make sense, because there's another separate chimney on the left hand side (it goes straight up). And all of the houses on this street appear to have that, so it must be original I assume.

 

[ashfp]

Just an update in case anyone ever had the same and is curious (obviously still worth getting your own professional opinion).

We had a structural engineer come view it and said the wall was not load bearing/supporting and we could either leave it or take it down. We have since taken it down.

It's worth noting that on the other side of the house you can see next doors chimney (the same one as this) comes right across the supporting party wall. So weight is taken by the original chimney breast as well as being across the wall.

The engineer suspects that the wall was temporarily built during the initial building of the chimney stack, but was only meant to be temporary (in terms of support anyway).