I don’t want the watch the whole video. What’s the takeaway?
He got planning permission, which means it is permitted.
He didnt have permission up until recently. He had said that to submit a request for planning he needed more detailed diagrams (more detailed than the "napkin" diagram he showed previously). He argued that by building some of the tunnel it allowed him to add the detail for the thickness of the concrete, depth of the tunnel etc that were design decisions he made while actually building it.