On the sidelines of the 2015 Paris climate summit, then-UK prime minister David Cameron and 19 other world leaders made a promise to double green energy research and development by 2020.
The United Kingdom is on course to break that promise. As a percentage of GDP, spending on low-carbon energy R&D has stayed sluggishly around 0.02 per cent since 2015, according to data from the International Energy Agency (IEA).