With Northern Ireland being the exception, where an “outside” handrail is required for all winder flights there is no specific guidance given in the Building Regulations guidance for England, Wales and Scotland. Guidance given in BS 5395-:2010 The British Standard Code of Practice should be considered if working in these areas of the UK.
This code of practice calls for handrails to be fitted to both sides of flights with a relaxation offered for private stairs with winder flights where the outside handrail may be omitted as long as the newel has a graspable newel cap.