Thanks everyone you for your valuable insight.
StructIET - yes you are right, it is a scissors stairs, I'm based in Eire. The stair is cantilevers off link bridges between two blocks and is a feature in the atrium space.
Done a similar design with a solid concrete stair and followed guidance...
apologies for not being specific.
The stair has no support at mid landing and are only supported at structural floor level i.e stringers are cantilevered off the floors!
Can anyone please direct me to a design guide for cantilever stairs in steel? I'm looking at one at the moment and any help on this topic will be appreciated.