Quartermass and the Pit.
The story first seen as a movie titled “5 Million Years to Earth. It was never forgotten as it was seen at the time of the grasshopper invasion here in Texas. So bad they ate the bark from trees.
It was found on Roku in the original version of BBC broadcast with a few others. Exactly which Roku channel carried it, no idea. Actually, it might have been found via the Wayback Machine and loaded from the Smart TV.
Quartermass/Pit (BBC Broadcast) is found on YouTube in several uploaded installments, along with other Quartermass episodes. Try Google asking for You Tube BBC Quartermass
Thanks. We really enjoyed it.