I seriously believe that is pure corruption. HighSpeed2 should cost a fraction of the price being quoted as well. It shouldn't take a country decades to pay back the cost of laying down rails in such a small country as ours. I estimate 10% goes to the project, 90% goes into peoples pockets without doing a days work.
Presumably in the future, with blockchain-style transactions, we'll be able to see where exactly the money went in such situations.
What makes you think contractors on public works won't use tumblers?
They wouldn't just need tumblers, they'd also need secret wallets. Public funds pay in to contractor wallet, ..., contractor wallet pays tumbler ... that should be enough to demonstrate corruption?