They had a stand at the Wired London show two years back. I love the idea, prescient perhaps to help with deliveries; but I can’t get my head past the capital

They had a stand at the Wired London show two years back. I love the idea, prescient perhaps to help with deliveries; but I can’t get my head past the capital cost of making the tunnels. Local news item from a few days ago: https://www.youtube.com/watch?v=VPppikqu5N0 https://www.youtube.com/watch?v=VPppikqu5N0