As someone that grew up in the UK in the 1970s and 80s with 3 TV channels that reached the majority of the UK, Greenpeace were a fixture on mainstream news. The past was somewhat different to today.
In the 1970s the BBC news programmes gave huge amounts of air time to Greenpeace and CND. Greenham Common and CND being given the most coverage.
When the only source of information is a daily newspaper, or nightly news programmes, a huge number of people can be influenced by whatever a channel like the BBC was broadcasting.
Unlike today where you can read wikipedia (!) or switch to one of a hundred other channels and simply just not watch the news.
TV set the agenda back then, and the course of nuclear sentiment for a few decades.
https://en.wikipedia.org/wiki/Anti-nuclear_movement_in_the_U...