We’ve been told that big finance is crucial to the transition to net zero, and billions of dollars are invested in so-called sustainable finance every year. But the BBC’s Climate Editor Justin Rowlatt, together with the Bureau of Investigative Journalism, have been looking into a new green finance product and found that not all is quite as it seems.

Their investigation has found an example of sustainable finance backed by the multi-national bank HSBC being used to help extract a vast new reserve of fossil fuels in Brazil. And it's not the only one. Some question how this can happen, while others defend it.

Producers: Sophie Eastaugh and Miho Tanaka