K1 building regulations is the approved document which covers stairs ladders and ramps.
Spiral staircase regulations scotland.
Bs 5395 part 2 1984 this states that a spiral serving 1 habitable room should have a 600mm clear width max rise of 220mm and centre going of more than 145mm.
Overall staircases in scotland are likely to be larger in width and length and take up more space than those elsewhere in the uk.
In k1 section 1 21 spiral and helical stairs the regulations refer you to a british standard bs5395 2 1984.
The rules and regulations for spiral staircases are still laid out by the british standard 5395 although the scottish regulations still require the 900mm clear tread width for a main stair as opposed to the 800mm mentioned in the bs.
If your spiral staircase complies with bs5395 then it also complies with k1 building regs.
When considering the building regulations for spiral staircases in the uk it is worth being aware that these can differ in scotland.
The document governing spiral staircase building regulations in the uk is british standard 5395 part 2.
Spiral staircases page of continental stairs.