Proportional representation

* Under some forms of proportional representation Labour could have won the election with an even bigger majority than it got under the first-past-the-post system, according to research commissioned by the Economic and Social Research Council and the Joseph Rowntree Reform Trust.

Two systems, the alternative vote and supplementary vote, would have given Labour 17 more MPs. But the single transferable vote method would have meant a smaller majority, while the additional member system would have yielded a minority Labour government.

This system gives the most "proportional" result with seats matching votes nationally.

The conference, at the University of Essex, ends on Sunday.