Some years ago, Sir David Attenborough wrote an article about his involvement in TVE's Earth Report series. There is much of interest, including the fact that programmes were sponsored by WWF at various times, and that he himself introduced each programme.
The series has been made possible by the generosity of WWF and the MacArthur Foundation, which have provided more than half the $900,000 it is costing to provide a regular service. Other finance has come from such sources as the Global Environment Facility, the World Health Organization, UNEP, and the Secretariat of the Ramsar Convention.
It would be interesting to know if the sponsorship was acknowledged in the Earth Reports shows. Attenborough, as a former Director of Programmes at the BBC, would presumably have known the rules.