The Electoral Reform Society (ERS) insisted it was now “long overdue” for all elections to be conducted using proportional representation (PR), as it claimed the method used to elect MPs to the House of Commons should be “consigned to history”.
The campaigning body used the anniversary of the Referendums (Scotland and Wales) Act on July 31 1997 to call for changes to be made.
Elections to the Scottish Parliament and Welsh Assembly are already conducted using PR systems – with both these devolved administrations having extended PR to local council elections too.
“English voters are in danger of being left behind,” the ERS said in a new report on the issue.
“Not only are the devolved parliamentary elections in Scotland and Wales run under PR, but both parliaments have legislated for the further expansion of PR systems into local elections in each country.”
Comparing the Holyrood election results with UK general election results in Scotland, the report noted that the last seven general elections in Scotland had seen the largest party win on average 75% of seats north of the border on an average of just 43% of the votes.
“In every UK general election since 1997, the largest party in Scotland has won a majority of Scottish seats on a minority of votes,” the report noted.
But in the six Scottish Parliament elections that have taken place over the same period, the largest party won on average 45% of the seats, having received 37% of the regional list votes in Holyrood’s system – where people have both a constituency and a regional ballot.
Willie Sullivan, senior director at ERS Scotland, said: “We’ve long known that Westminster’s winner takes all voting system has been failing Scotland – creating a virtual one-party state that sees millions of voters’ preferences ignored.
“Across the last seven UK general elections, the largest party has won on average 75% of Scottish seats with just 43% of the votes.
“Compared to the results in the Scottish Parliament, that’s a result four times as warped in terms of seat share – with FPTP (first past the post) delivering disproportionate results that leave everyone worse off.”
With Scotland having had PR elections since the first Holyrood ballot in 1999, he said that “voters know that their ballots will count”, adding that “it’s only votes for Westminster that are holding Scotland back”.
Mr Sullivan said: “Reform is vital if we’re to have a House of Commons that represents the interests and votes of the people of Scotland.
“Until then, every voter will continue to lose out. We need a fair and proportional voting system for Westminster – it’s time that our UK Parliament followed Scotland’s lead and made sure every vote counts.”
A UK Government spokeswoman said: “Britain’s long-standing electoral system of first past the post provides a clear, well-understood link between constituents and their representatives in Parliament.
“This ensures greater accountability and allows voters to kick out those who don’t deliver.
“The British public voted to keep Britain’s electoral system in the 2011 UK-wide referendum and the voice of the people in this referendum should be respected.”