They have tabled amendments to the Constitution and Governance Bill which would have elections to the House of Commons run under the Single Transferable Vote System of proportional representation, as is used for elections to the Northern Ireland Assembly.
Yet the Lib Dems have gone so far as to seemingly bypass the independent Boundary Commission altogether, since they have proposed setting in statute the boundaries for a House of Commons of 512 MPs under STV.
As their fantasy new schedule 3 states:
"Notwithstanding anything in the Parliamentary Constituencies Act 1986 or in any other relevant legislation, the parliamentary constituency boundaries and the number of members to be elected for each constituency shall be…"
Some counties and cities would be a single constituency, such as Suffolk (6 MPs), Northumberland (3 MPs). Leeds (6 MPs) and Manchester (4 MPs). Larger counties wold be divided up into two or three constituencies, whilst the Isle of Wight would become a two-member seat and the existing Orkney and Shetland would be renamed Northern Isles and return just one MP (it's currently a Lib Dem seat).
As I say, it's the stuff of fantasy, but interesting to see it all set out on paper.
Presumably the Lib Dems have done the maths and computed what would probably have happened at the last general election on these boundaries. Does anyone have those numbers?