Jenkins Commission: New-style voting: how it would work

In the polling booth

Under the system proposed by Lord Jenkins, each voter would go into the polling booth with a two-part ballot paper, perforated down the middle.

On the left-hand side would be the traditional form, listing the candidates for that constituency and their party labels. But instead of marking just one candidate with a cross, voters can use numbers to rank some or all candidates in order of preference.

The right-hand side would be a new style of ballot paper, on which voters select an MP or MPs to represent a larger area, usually covering six or seven constituencies.

On this side electors are given only one vote, but can choose to vote for an individual candidate or for a party. If they vote for a party, then the party will decide which candidate benefits from those votes.

After voting, an electorwould separate the ballot paper and post each half in different boxes.

At the count

Constituency MPs would be elected by counting first-preference votes. If no candidate has more than 50 per cent of the votes in a constituency, the bottom-placed candidate is eliminated and his or her votes are transferred to the second-preference candidates. If the ballot papers have not been marked with a second preference, they are discarded. If necessary, the process is repeated until a candidate emerges with a majority of the votes.

In each super-constituency, the second votes are divided into piles for each party and counted. Each party's share of the vote in the area is compared with its share of constituency MPs in that area. One or two "top-up" MPs are then elected for the party or parties which are most under-represented: which candidate is elected would depend on his or her place on their party's list and on the number of individual votes they receive.