Panorama investigates the green projects that say they can help brands cancel out their carbon emissions. But do the claims stack up?

Filmed, Produced & Directed by Jess Kelly
Executive Producer (BBC): Tom Stone
Executive Producer (DM Productions): David Modell
Producer: Ben Bryant                                                           Supervising Producer: Ben Ferguson                                            Production Executive: Erin Bottari                                                  Junior Production Manager: Federica Schiavello