Scottish Referendums

The Additional Member System

Both the Scottish Parliament and the Welsh Assembly are to be elected through the Additional Member System.

Each elector will cast two votes: one for a constituency MP and one for the party of his or her choice. The constituency MP is to be elected along the boundaries of current parliamentary constituencies on a "first past the post" basis.

The second vote, that is the vote for the additional member, will be allocated to a party list rather than to an individual candidate. Each party will draw up a list of candidates for each of the current European Parliamentary constituencies.

In Scotland 7 additional members will be elected from each of the current 8 European Parliamentary constituencies (56 seats). In Wales, 4 additional members will be elected from each of the current 5 European Parliamentary constituencies (20 seats). Each European Parliamentary constituency is made up of between 7 and 9 Westminster Parliamentary constituencies.

Additional Member seats will be allocated according to the number of constituency seats gained within the European Parliamentary constituency.

the number of votes cast for each party within the European constituency will be counted.

the number of constituency seats won by each party will be counted.

the number of votes cast for each party will be divided by the number of constituency seats won by that party plus one.

the party with the highest number of votes after that calculation gains the first additional member. This is the party with the greatest disparity between votes cast and seats won. It is not the party with the greatest number of seats.

the remaining additional members are allocated in the same way (a total of 7 in each European constituency in Scotland and 5 in each European constituency in Wales), but additional member seats already allocated are included in the total.

The effect of the Additional Member System is to provide a re-allocative mechanism, so that a party's share of the vote is reflected in the seats it gains. It will benefit parties with a share of the vote that is not sufficiently large, or sufficiently concentrated, to win many seats under a first past the post system.

Click here to see what the effect the additional member system might have on a Scottish Parliament.