NICOLA Sturgeon’s claim to have a renewed mandate for an independence referendum is based on a “warped” result for the SNP in the general election, according to a new study.

The Electoral Reform Society (ERS) said Scotland produced the “most disproportionate” result of any part of the UK because the SNP’s share of MPs so far outweighed its share of the vote.

It said Ms Sturgeon’s party won 81 per cent of the 59 Scottish seats in December on 45% of the vote because of the in-built unfairness of the first-past-the-post voting system, which the SNP itself wants replaced.

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It said the SNP’s performance “delivered one of the most warped results in the UK, with a 22 percentage point increase in seats for an eight-point increase in votes”.

The ERS calculated that under proportional representation, the SNP would have won 26, 28 or 30 seats, depending on which PR system was used, rather than the 48 it did.

Two of those results would have given the SNP a minority of seats, leaving Ms Sturgeon unable to claim the SNP had emphatically won the election or that Scotland had backed Indyref2.

The ERS also applied a measure which assesses the extent to which an election result deviates from proportionality, the DV index.

PR voting systems, because they are approximate, typically score 5 to 8.

Across the UK, the general election result scored 16.2 on the DV index, showing it was less proportionate.

But in Scotland, it was 36.4, which the ERS called "starkly disproportionate".

The Herald:

From 35 seats in 2017, the SNP won 47 seats last year, plus one where the candidate was described as SNP on the ballot even though he had been suspended from the party.

The latter was the result of the party taking action against Neil Hanvey in Kirkcaldy & Cowdenbeath over alleged anti-semitism after the ballot paper could be changed.

He is now technically an Independent MP, but sits and votes with the SNP at Westminster and hopes to return to the party fold.

READ MORE: Scottish independence support maintains lead in latest poll 

After the election, the SNP cited the 80% of seats won in its demand for Boris Johnson to give Holyrood the power to hold a legal independence referendum, with Ms Sturgeon saying the result “strengthened” her mandate.

The Prime Minister refused, while Tory MSPs and MPs pointed out the SNP won less than half the vote, a complaint the SNP flatly dismissed.

However, today’s ERS report says the election left the vast majority of Scottish voters “voiceless” as their choices were not reflected under the winner-take-all voting system.

It said that of 2.8m votes cast north of the border, 1.9m or 68.5% were “effectively ignored” as they did not contribute to the result because they either went to candidates who were not elected (1.5m votes) or were surplus votes for winning candidates.

The report said: “Over half of voters… do not have an MP they voted for.

“In Scotland, voters of both the Conservatives and Labour suffered, with 80% of Conservative voters and 95% of Labour voters going unrepresented, compared to just 15% of SNP voters.”

The UK is the only EU country still to use a first-past-the-post voting system.

The ERS Society, which campaigns for a fairer voting system, said it was to the SNP’s credit that the party’s policy is to switch to a PR method, but still described the result the SNP enjoyed last year as based on an “insult to the millions who want to be heard”.

Dr Jess Garland, Director of Policy and Research at the ERS, said: “Voters in Scotland are being cheated out of fair representation in the Commons.

“The huge scale of unrepresented votes, in Scotland and across the UK, represents a democratic crisis that has to be tackled. It’s time to ensure seats match how people want to vote."

Tory MSP Murdo Fraser said: “First-past-the-post is not a perfect system - but PR has its own limitations.

“FPTP works in delivering government for the UK with a working majority, providing stability, so we would be reluctant to see a change to the voting system - even though that might benefit us in Scotland.”

SNP depute leader Keith Brown said: “The SNP are long-standing supporters of PR, which is in place for Holyrood and council elections in Scotland. While we would support changes to FPTP and the abolition of the Lords, it is clear the only real democratic solution for Scotland to ensure it always gets the government it votes for is to be independent.”