HS2 Aerial view looking directly down the shaft at Little Missenden
from:https://mediacentre.hs2.org.uk/news/tunnel-progress-as-hs2s-florence-and-cecilia-reach-little-missenden
Mark Thurston, the CEO of Britain's mega project High Speed 2 (HS2).
source: HS2 media release https://mediacentre.hs2.org.uk/news/hs2s-ceo-to-step-down-after-six-and-a-half-years