The list of virtues possessed by Toyota Prius drivers just keeps growing. There is environmentalism, of course, and - as oil prices skip toward $150 a barrel - economic savvy. Increasingly, there is also patience.

Waiting lists for Priuses have expanded sharply as demand outstrips the Japanese carmaker's capacity to build the petrol-electric hybrid vehicles. Toyota - normally a paragon of supply-chain management - admits to "bottlenecks", particularly in batteries, which have slowed turnover even as drivers clamour for more fuel-efficient cars.