This option is an "add-on" to - and is not an inherent part of - the main PFPTP ProFirst proposal. It would require constitutional changes to bring it into being, but is aimed at achieving an even more democratically representative Parliament, in which minor "voices" could then be heard. The supernumerary (literally "above the usual number") option's main features are:
The Supernumerary MP option, if adopted, would have the effect of enfranchising those people who vote for minority parties which normally achieve no parliamentary representation. It would also require a further reduction in the overall number of constituencies (below the currently-mooted 600) so that the total of MPs, including supernumeraries, did not exceed the overall target.
A demonstration of how this might work is shown in the accompanying table, which is based on the 2010 Election results, but with the seats notionally adjusted by combining constituencies to maintain an overall total of 650 seats, even with the addition of some 43 supernumerary seats.
While it might seem that this proposal would be likely to increase the number of minor or "loony" parties, in fact it might well have the opposite effect. Most of those parties at present are probably collecting "protest" votes from people who feel they stand no chance of being represented by a candidate of their choice and therefore want to register their dissatisfaction. For a party to achieve even one supernumerary MP it has to collect a substantial proportion of the votes cast country-wide, and so there will be pressure to amalgamate minor parties and even many otherwise independent candidates under a single banner with a reasonably broad appeal.