A SECRET list of donors to the anti-independence group Scotland in Union has been inadvertently released by the Electoral Commission.

The elections watchdog failed to redact the material properly when it included it in a freedom of information release published on its website earlier this month.

A simple “cut and paste” procedure was enough to reveal the names of scores of donors, what they gave and when.

Much of the same material was released in a Scotland in Union (SIU) security breach at the New Year, when a donor spreadsheet was sent to Nationalist websites and SIU alerted the police and the Information Commissioner.

The Electoral Commission published the FoI release on April 17.

It is not known how many people downloaded it or spotted the security flaw.

News of the blunder coincided with a report that SIU, which opposes another referendum, met controversial data firm Cambridge Analytica (CA) last year.

The Open Democracy website reported SIU founder and deputy chair Will Ramsay boasted of a contact to a fundraising dinner in London in November.

Mr Ramsay was quoted saying: “The SNP have an army of supporters, and a sophisticated database - I know that from speaking to Cambridge Analytica the other day, who are not working for them, thank goodness.”

The SNP has recently been under fire over its contact with CA in February 2016, when an “external consultant” met the firm.

CA has since been linked to a privacy breach affecting up to 87m Facebook users.

The Electoral Commission last night removed the faulty document from its website.

A spokesman said there had been a “technical issue” with redactions which enabled access to personal information, adding: “We regret this error, are investigating as a matter of urgency and will provide further information at the earliest opportunity.”

SIU were approached for comment.