Britain's ‘divisive and disproportionate' voting system is contributing to the break-up of the union and leading to a local ‘postcode electoral lottery' a new report claims.

A comprehensive study of May's 2015 general election, published by the Electoral Reform Society on 1 June, has revealed the ‘most disproportionate ' result in British history.

The ERS looked at how Parliamentary seats were distributed following the vote on 7 May, and assessed how that reflected the number of votes each party gleaned locally.