But Mr Diggle said that “achieving climate objectives actually helps deliver on the [ECB’s] price stability objective, given the long-term risks involved in climate change”.

Another argued that the plan was simply "a bad idea".

Stefan Kooths, research director at the Kiel Institute for the World Economy, said he thought the ECB was "very likely" to adapt its monetary policy to meet climate policy targets, even though he thought this was "a bad idea."

Of course, assuming this becomes policy reality, it would open the door to the central bank openly buying shares of 'green' companies, while their 'brown' rivals are left to languish in price-discovery hell.