The treasury obviously has no clue what the "Blockchain" is about. They can tell the banks all they want, it won't lead to any meaningful results. It's pure activism born from the fear that the UK might loose its status as a world financial center. However that's exactly what's going to happen.
Private, centralized blockchains are of no use, they only waste resources. All these bank projects will just burn a lot of money that could be used better elsewhere. A blockchain makes only sense as a tool to enable a decentralized currency. All secondary applications envisioned for riding on a blockchain directly depend on the extent of decentralization and network size for their security. In that regard, no private blockchain will be able to compete with Bitcoin.
However, banks will have to learn this lesson the hard way...
ya.ya.yo!