In February, the Bank of England released a consulation paper for a digital pound. Just heard about it, the deadline is in a week. The pdf can be downloaded from this page:
There’s also an accompanying Technology Working Paper (also a downloadable pdf) which talks about the “core ledger” from page 48, and blockchains are mentioned on pages 50-51:
Energy usage is on p44, mentions proof of work, but not proof of stake.
Ethereum and Avalance get mentions on page 74.