More than half of the world’s population lives under an energy system that its advocates say can tackle fuel poverty, improve crumbling housing stock and reduce energy demand. And to cap it off – when properly designed – it would not cost the taxpayer anything.

The so-called rising block tariff or national energy guarantee system (NEG) are almost unknown in Europe but operate successfully in many other countries and regions – from Japan, South Korea and China to Bangladesh, India and California.