Source: http://books.google.co.uk/books?id=z0Z3DxacC9IC&pg=PA457&lpg=PA457&dq=dinorwig+£425+million&source=bl&ots=O2Ixg4eXU8&sig=GT91GlMM9GLN4nISC3NL18Suuxo&hl=en&ei=9aJdTZq1KIqv8QOIpPWwCw&sa=X&oi=book_result&ct=result&resnum=5&ved=0CDcQ6AEwBA#v=onepage&q=dinorwig%20£425%20million&f=false