This programme was made by Martin Durkin who directed the "Against Nature" series some time ago on Channel 4. The Independent Television Commission, reviewing Against Nature in response to hundreds of complaints, handed down one of the most damning rulings it has ever made. For details see the Monbiot article
Far Left or Far Right. I find it hard to believe that Channel 4 gave him another bite at the cherry!
Whilst it is not beyond the bounds of possibility that the vast majority of climate scientists are part of a huge global conspiracy, it is certainly extremely unlikely. The best web resource I have found which attempts to explain how the current consensus was reached by scientists is Spenser Weart's
The Discovery of Global Warming website which accompanies his book of the same title.
Don't believe anything you see on TV:-)