Dragons' Den investor Deborah Meaden and Radio 5 Live's Felicity Hannah are on a mission to discover what big business is doing to clean up its impact on the planet. After listeners got in touch to ask about green and ethical pensions, the pair discover how the trillions of pounds we put aside for our retirements has the power to change the world. So how can we track that cash and make sure it's being invested in the best and greenest way possible?

And what even is a "green" pension fund? The boss of Aviva Investors tells Deborah and Fliss how he believes rather than pulling out of polluting stocks, pension funds should use their power and influence to force "brown" companies to go green.

Producer: Lexy O’Connor