Canada

In Canadian law, the "declaratory power" (or "federal declaratory power") is linked to the Works and Undertakings

Works and Undertakings

In Canada, the Local Works and Undertakings clause under section 92 of the Constitution Act, 1867 divides communication and transportation-related matters between both the federal and provincial governments...

 clause of the constitution, and allows Parliament to declare that public works

Public works

Public works are a broad category of projects, financed and constructed by the government, for recreational, employment, and health and safety uses in the greater community...

 in one province are for the "general advantage of Canada" or "for two or more of the Provinces" rather than just for the advantage of one province; this gives the federal government authority to take control of these projects. In general terms, the works thus described tend to be part of the national infrastructure

Infrastructure

Infrastructure is basic physical and organizational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function...

.

The declaration must be made by the passing of legislation, but in addition to declaring specific works, whole classes of work can be defined as being "for the general advantage of Canada" by default; the Atomic Energy Control Act, for example, deemed all nuclear power plants to fall into this category. From 1867 to 1961 there were 470 uses of the declaratory power, of which 84% related to railways.

Scotland

In Scots law

Scots law

Scots law is the legal system of Scotland. It is considered a hybrid or mixed legal system as it traces its roots to a number of different historical sources. With English law and Northern Irish law it forms the legal system of the United Kingdom; it shares with the two other systems some...

, the "declaratory power" is an unusual power held by the High Court of Justiciary

High Court of Justiciary

The High Court of Justiciary is the supreme criminal court of Scotland.The High Court is both a court of first instance and a court of appeal. As a court of first instance, the High Court sits mainly in Parliament House, or in the former Sheriff Court building, in Edinburgh, but also sits from time...

, which enables it to declare behaviour to be criminal, even if that behaviour had not been previously defined as criminal activity.

This power has been used conservatively in the modern period, generally only in cases where an act is clearly comparable to an existing crime; it has, for example, been used to declare the selling of kits for glue-sniffing criminal. As the specific boundaries of many offences are left somewhat loosely defined, it can be difficult to distinguish the application of the declaratory power from cases where the court interprets existing legislation to cover new situations.