Trading activities may expand by increasing the scale of existing production, by mergers, by entering new markets or by introducing new products.
The question whether there has been an expansion of an existing trade, or a discontinuance of a former trade and commencement of a new one, is primarily a question of fact to be determined by the appeal commissioners or, now, tribunal. The courts will only disturb such findings of fact in certain restricted cases. Cases dealing with the addition of new premises, activities, etc. have included: