Post-election number-crunching

Although less so than others in the past, last week's General Election result threw up some clear differences between the votes won by each political party and the number of parliamentary seats which that gave them.

First Past the Post as a voting system obviously favours parties who are able to build up large votes in individual constituencies, even if some of those are then wasted because they end up surplus to returning their candidate there, and punishes those whose support is spread more thinly across the country. So what would the House of Commons look like if a proportional representation voting system had been used for last week's poll?

There are different forms of PR, from single transferable vote in multi-member constituencies to national lists with thresholds for representation, or a mixture of the two, but assuming a strict correlation between votes cast and seats won it would have given the Conservatives (42.4%) 275 seats rather than 317, Labour (40%) 260 rather than 262, the Liberal Democrats (7.4%) 48 rather than 12, UKIP (1.8%) 11 and the Greens (1.6%) 10 rather than none and one, the Scottish National Party (3%) 19 rather than 35, and the Democratic Unionists (0.9%) who with their 10 Northern Irish seats now hold the balance of power half that with only 5 MP's returned to Westminster.

The outcome might still have been a Conservative minority government, albeit one short of the necessary votes to get its legislation through Parliament without appealing to parties apart from the DUP, but Labour too would have had a possible route to power with the support of other centrist and centre-left parties such as the Lib Dems, Greens and SNP.