THE former chair of the campaign that delivered the Scottish Parliament has said Westminster should impose a “super-majority” on the next independence referendum.

Nigel Smith said setting a threshold of 55 per cent for a successful Yes vote, for example, would show there was a national consensus for radical change better than a majority of 50 per cent plus one.

Writing in the Herald today, Mr Smith, who led the successful Yes-Yes campaign for Holyrood and devolved taxation in 1997, said there was no evidence of such a consensus at present.

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Given the rest of the UK would not have a say on Scottish independence, he said Theresa May would be right to insist upon proof of consensus through a higher threshold for Yes.

In the 1979 vote on a Scottish Assembly, the Yes side won the most votes, but was denied victory as less than 40 per cent of the electorate as a whole had voted for devolution.

The notorious 40 per cent rule, devised by the arch devo-sceptic Labour MP George Cunningham, meant people who didn’t vote at all effectively helped defeat the Assembly plan.

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Mr Smith’s proposal would be different: a 50 per cent-plus threshold among those voting.