KEIR Starmer has vowed to stop using data on voter religion in Scotland to estimate the success of his party in elections.

The Labour leader said the practice, revealed from a leaked memo earlier this year, was “totally inappropriate”.

It comes after the leaked “key seats strategy” document, which circulated online in August, showed that the party had used data on the proportion of Catholics in Scottish constituencies to “distinguish better between Labour and SNP supporters”.

The document was created prior to the 2019 General Election, while the party was under the rule of Jeremy Corbyn, and was described as “humiliating” by Scottish Labour sources.

It stated: “There were differences for Scotland, where data availability is slightly more limited.

“Some constituency-level demographics, such as employment categories and percentage in poor health, were absent. However, one variable – proportion of Catholic residents by constituency (%) – was included for Scotland for the purpose of helping to distinguish better between Labour and SNP supporters.”

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Starmer was asked by The Herald on Sunday what he thought of the polling data and the fact Scots’ religions were being used as a judgment for party allegiance, and whether it would continue to be used in future. He said the planning methods “relate to a period before I was leader” but added: “From what I know, it looks to me to be totally inappropriate.”

He added: “It certainly won’t be happening under my leadership”.

The revelations in the leaked memo had the party branded “the Morris Minor of politics” by SNP MP Angus MacNeil, while others said it showed the party was “finished” in Scotland.

Alongside the plans to use religion as a yardstick for polling success, the document also stated that the party thought the public did not think it was a serious rival to the SNP in Scotland.

It suggested that party funds would be better spent challenging seats in England and Wales where they were more likely to have success than attempt to win in Scotland. It also predicted that seven MPs would lose their positions in Scotland.

Following the poll in December, the Labour party was reduced to just one Scottish MP – shadow Scottish secretary Ian Murray, who represents Edinburgh South.

However, since Starmer took the top job earlier this year, he has made every effort to highlight the party’s new attitude and has been keen to shed the image of Labour created under Corbyn. He has held several virtual “Call Keir” sessions with Scottish voters since he took over, including one with the constituents of shamed MP Margaret Ferrier earlier this week.

Following the discussion he told The Herald that regaining the trust of the Scottish electorate was a vital priority for him, and key to what he wanted to achieve as party leader. He also said that winning back votes in Scotland was going to be a “joint effort” between the UK and Scottish Labour parties.

Starmer added: “I was up in Scotland a few weeks ago with Richard Leonard planning out how we’re going to run into the May election which obviously matters hugely to us.

Richard and I, Scottish Labour and Labour know that we have got to rebuild trust in Scotland.

“We’ve got to rebuild that trust across the United Kingdom, particularly in Scotland.

“There’s a job of work to do and it’s very much a joint responsibility.”

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Annie Wells, Scottish Conservative MSP for Glasgow, previously criticised the use of the Catholic data.

She said: “It’s welcome that Labour have now confirmed this outdated data won’t be used again by the party in Scotland.

“However, it was astonishing that Scottish Labour felt it was appropriate to use this data in the first place. It showed how out of touch the party is with voters in today’s Scotland.

“That’s why so many ex-Labour voters backed the Scottish Conservatives in recent elections.”