I have it on reliable authority that the first Viking to be returned to service from Southern Sailplanes was billed to the taxpayer at a figure in excess of £100,000 New ASK21s are around €80,000 to buy. One really couldn't script it!
There used to be a DEFCON (in the 112 series) that, if called up and implemented, would prevent this. There was an associated DGDQA spec setting out how to implement it, and PUS issued mandates on the financial aspect. If you didn't know them by heart, you were pouring money down the drain. They fell into disuse some years ago when non-technical staff were permitted to self-delegate engineering/airworthiness/financial authority, but didn't have the knowledge to know to use them. Commercial contributed to this, as they didn't like the fact it made a nonsense of their claim that only they can legally commit MoD to contract. As ever, same solution. Implement the regs. It's what they're for.