Saw this staircase on a survey a few weeks ago, typical of its age – probably dating to the mid to late sixties. It looks good [to some eyes] is airy and open but doesn’t comply with building regulations. The lack of a handrail and balustrade is the concern here. The building Regulations are not retrospective and enforcement action is not really very likely if an occupier takes the handrail off but it is likely to come up as a problem at resale when the house is surveyed.
The building regulations require a handrail and balustrade in dwellings where there is a drop of more than 600mm, the handrail should be at 900mm height, if there are openings in the balustrade then a 100mm sphere must not be able to pass through them and the whole unit should not be easily climable by children. A handrail is required on both sides of the width exceeds 1000mm, for ease of use by disabled and mobility impaired users we would recommend a handrail on both sides whatever the width of the stair. Open risers like these are acceptable if each tread overlaps by minimum of 16mm