I had no idea this market existed until yesterday but it seems that you can buy paper stock certificates of long dead companies. Oldstocks.com is one site, but there are others, including eBay.
You can, for instance, buy a 1962, signed, Harley Davidson certificate, for £3,995, down from $5,000. Likely far more than the stock itself was ever worth when it was actively traded. This, like the Mark Twain quote about land, is a market that works "because they don’t make them any more."
What, then, am I bid for
– the Emergency Services Network business case signed by the then SRO?
– the ID cards business case as signed off by the Prime Minister?
Long dead projects could pay off their debts through selling off assets that are unexpectedly worth something.