ANTI-INDEPENDENCE campaign group Scotland in Union has been thrown into crisis and could face a significant fine after the private details of donors were leaked to Yes-supporting websites and newspapers.

Over the weekend an anonymous email account sent files to Wings Over Scotland, Bella Caledonia and The National – a damaging breach in security that is likely to leave supporters furious.

The spreadsheets used by the group contain a mixture of recorded contributions, potential donors and gossip, and the leak is a hammer blow to an organisation that has been supported by some of the UK's wealthiest people.

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Strict laws around personal information make it difficult for The National to share much of what is contained in the leaked files.

Scotland In Union says it has reported the leak to police and information watchdogs, but it faces a possible investigation which could lead to sanctions and a huge fine.

The main “potential donors” list includes many of the UK’s wealthy elite, with major landowners, aristocrats and CEOs of companies all listed. Featured are Earls, Lords, Viscounts, Colonels, Majors and Sirs. Many names are followed by “Esq” or preceded by “Hon.” Many have already donated to the organisation, or have pledged to do so.

Scotland in Union claims to be a “grassroots” campaign.

Next to some names are notes outlining who they work for, how they made their money, how likely they are to donate and what connections Scotland in Union has with them.

Also contained in a separate part of the document is a list of Scotland’s richest people, with the names of Brian Souter, Sean Connery and lottery winners Colin and Chris Weir – all independence supporters – scored out.

The three leaked files contain the names, postal and email addresses, home and mobile phone numbers of hundreds of supporters and potential donors.

Wings Over Scotland first published pictures of the donor spreadsheet showing dates and amounts but kept names of individuals hidden. Those images were later removed after the blogger received a letter from the group’s lawyers. The Yes-supporting Bella Caledonia website also said it had received the data dump.

The three files released over the weekend are named “Potential Funders”, “Prestonfield Dinner”, and “Will and Angus Lunch attendees”.

Will is likely the group’s vice-chair, Will Ramsay, and Angus is believed to be businessman and prominent supporter Angus MacDonald. The Prestonfield dinner was a £250-a-head meal held in a five-star hotel in the capital in 2016.

Guests included Alistair Darling, the former Labour chancellor; Willie Rennie, leader of the Scottish Liberal Democrats; and Andrew Dunlop, under-secretary of state for Scotland.

Diners were offered the chance to bid thousands for prizes including a stay in a luxury chalet in the Swiss Alps. The auction guide described the prize as “a fabulous chalet and a family home, with six bedrooms sleeping 12, all en suite.”

It added: “Although the chalet does not come with a chalet girl, we will provide one for you."

Other prizes included a four-day “extravaganza of polo and amazing parties in Jodhpur for two ... rubbing shoulders with the maharajah” and a “holiday of a lifetime” in a private game reserve in Botswana for 10 people.

Guests were also tempted with the prospect of hind stalking near Fort William, a long weekend shooting pheasant, woodcock and snipe in Argyll, and a week-long fishing holiday in Glen Lyon. A signed copy of a JK Rowling novel was also on offer, and diners with slightly smaller pockets were invited to part with £100 for a raffle ticket to win a Mini Cooper convertible. The dinner raised an estimated £300,000.

According to the Electoral Commission, the anti-independence group spent £73,000 in the run-up the snap General Election in 2017. That was after spending £26,670 on the Scottish Parliament election in 2016.

Scotland In Union was set up shortly after the 2014 independence referendum to campaign against a second vote on independence.

A spokesman for Scotland In Union told The Herald: “All information on our supporters is protected and held securely in accordance with best practice and we regret internal documents have been shared with external parties. We have reported the matter to the police and the Information Commissioner.

"We have taken all necessary steps to make our affected supporters aware and will continue to investigate how these documents have been misused.”

The Information Commissioner’s Office (ICO) has the power to issue fines of up to £500,000.

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Last year, insurance firm RSA was hit with a £150,000 fine after allowing a digital copy of 60,000 customer files to be stolen from a supposedly secure room.

“For no good reason, RSA appears to have overlooked the need to ensure that it had robust measures in place despite having the financial and staffing resources available,” the ICO said in its judgment.

There was no mention of the data leak in Scotland in Union’s latest missive to supporters on Monday, where they said the fact that “Auld Lang Syne will be sung as far afield as Australia and the US and many a whisky will be poured to toast the opportunity of a new year in different parts of the world” showed that Scotland’s place in the UK “has helped give it a platform to the world.”

The National’s attempts to contact the person behind the leak were unsuccessful, with the email address used to send the files seemingly now deleted.