How much is your Labour leadership vote worth?

The disproportionate power wielded by MPs in the electoral college may come under scrutiny.

The Labour leadership election caught fire last night with Jon Cruddas's endorsement of David Miliband (exclusively revealed by the NS) and the emergence of clear red water between the Miliband brothers.

But one subject to which commentators have devoted insufficient attention is Labour's electoral system. As most of you will know, the big decision lies with an electoral college split equally three ways between the 271 MPs and MEPs, all party members (around 165,000) and members of affiliated trade unions and socialist societies (an eclectic bunch that includes the Fabian Society, the Jewish Labour movement, the Christian Socialist Movement, Scientists for Labour and the Labour Animal Welfare Society; you can see a full list here).

As a result, the vote of one MP is worth proportionally more than those of hundreds of regular party members and thousands of affiliated members (of whomh there are an estimated 3.5 million). This contrasts with the system used by the Tories and the Lib Dems, under which candidates are nominated by MPs before going forward to a membership ballot.

To display the idiosyncracies of the Labour system better, here are some key figures:

The vote of one MP is worth the votes of nearly 608 party members and 12,915 affiliated members.
The vote of one party member is worth the votes of 21 affiliated members.
An MP's vote is worth 0.12 per cent of the total electorate, a party member's vote is worth 0.0002 per cent and an affiliated member's vote is worth 0.00000943 per cent.

David Miliband currently enjoys the support of the largest number of MPs (101, after the Cruddas endorsement) and the highest number of Constituency Labour Parties (165). Should the former win the day for him, it would be surprising if some Labour activists didn't begin to question the vastly disproportionate power wielded by MPs under the present arrangements.