Almost everyone can find something to dislike about the coalition's proposed boundary changes. The plan to equalise constituency sizes will disrupt traditional boundaries and historic communities without correcting the electoral bias towards Labour (which is not due to unequal constituencies). In addition, the redrawn boundaries will take no account of the 3.5 million people not on the electoral register, producing a skewed electoral map that ignores millions of eligible voters.

Meanwhile, the accompanying 10 per cent reduction in the number of MPs will not be matched by a commensurate reduction in the number of ministers, further reducing parliamentary accountability and swelling the payroll vote. Aware of all these objections, the coalition is still planning to abolish public inquiries into boundary changes -- an extraordinary act of non-consultation.

There remains one last outpost of resistance -- the House of Lords. Today, peers will vote on a Labour motion to refer the bill to a parliamentary select committee local appeals process, something that could delay the legislation for months and halt the planned referendum on the Alternative Vote. Charles Falconer, who is tabling the motion, argues that the bill can be declared "hybird" because it singles out two constituencies -- Shetland and the Western Isles -- for special treatment.

There is no such exemption for the Isle of Wight, which with 110,000 voters is too big to fit the prescribed 76,000 limit, but too small for two MPs. The extra 34,000 constituents will be bolted onto a constituency in Hampshire -- an absurd solution that will require the MP to travel back and forth between the mainland and the island. Like an old colonial bureaucrat, Cameron is planning to draw lines on the map that take no account of geography, history and identity.

The solution is clear: to split the legislation into two separate bills by decoupling the boundary changes from the referendum. This would allow pro-AV Labour MPs to unambiguously support the bill while maintaining their opposition to the rest of the reforms. Conversely, Conservative MPs could vote against electoral reform without fear of jeopardising the coalition's boundary changes. It may not make much political sense to David Cameron (the referendum was a quid pro quo for the boundary changes) but it would make a lot of parliamentary sense.