Modular staircase

A modular staircase suitable for use in a structure, the staircase comprising:

• at least one stringer having an elongate axis, the stringer configured for extending between a first floor of the structure and a second floor of the structure, the stringer having a box-section profile and at least two flanges projecting from a first wall of the stringer profile;
• at least one spigot configured as a box-section profile for mounting with the at least two flanges, wherein one side wall of the box-section profile able to locate in adjacency of and/or to abut one of the at least two flanges, and with an opposing side wall of the box-section profile able to locate in adjacency of and/or to abut another one of the at least two flanges, and such that an axis of the spigot is able to extend at an angle with respect to the stringer elongate axis;
• and
• at least one tread support for coupling to the stringer via the at least one spigot, wherein when the angle of the spigot axis is adjusted relative to the stringer elongate axis, the tread support is able to be orientated at an angle relative to the stringer in-use.