After much debate, here we have it — Scottish Government guidance issued this afternoon, which comes into effect as of today, 6 April 2020, reviewable in three weeks.
Any work on non-essential services must be halted. Non-essential services include (by way of example) domestic housing, schools, office buildings, leisure, retail.
In short, it's only essential work if it is critical to the national response to COVID-19, or part of the infrastructure essential for the containment and treatment of the virus and the distribution of food, essential supplies, utilities and communications to households.
Even then, the requirement to comply with health and safety remains — and operations need to cease if those requirements cannot be met.
So, unless within one of the defined essential services or projects, or works can be completed (safely) within the next five days, sites need to close now, with companies required to put in place suitable arrangements for site security and safety.
The full effect of the guidance will need to be digested but there we have it, no more speculation or debate.
Operations should be shut down safely and securely, ensuring that partially-built structures are safe, and if necessary wind- and water-tight, associated equipment is properly stored, and sites have suitable security for the duration. Exceptionally, if sites can be safely completed within 5 working days they can be completed.