DAVID Mundell is being told to come clean over so-called “dark money” donations taken in by his team during the 2017 election.

According to reports, the Secretary of State for Scotland’s campaign manager had half his salary paid by the shadowy Scottish Unionist Association Trust (SUAT).

New records, uncovered by the Herald, revealed that the Scottish Borders Conservative & Unionist Association (SBCUA), which covers the Tweeddale part of Mundell’s Dumfriesshire, Clydesdale and Tweeddale seat, split the cost of the 2017 general election campaign with the SUAT.

The cost split was not given, but official election invoices listed the campaign manager costs as “103 days @ 50%” and “38 days @ 50%”.

The SUAT gave the SBCUA at least £12,336 in 2014 and £6,168 in 2015.

The groups also jointly funded a campaign manager for Tory MP John Lamont in Berwickshire, Roxburgh & Selkirk in 2015 and 2017.

During the 2015 election, the chair and treasurer of the SBCUA was former Merrill Lynch consultant Robert Miller-Bakewell, the chair of the SUAT.

He was also deputy chair and deputy treasurer of the SBCUA at the 2017 election.

He had served on the Tory executive in 2000, but left in a furious row over infighting.

During a BBC Radio Scotland interview last month, Mundell was cagey when asked if he had benefited from the trust’s cash.

He said: “I personally have not received cash because we go through a process of funding associations and I am confident that over the full period during which I have been involved in politics, all donations I have received from any source have been appropriately declared.”

Asked how much money his campaign had received, he said: “That is a question that can be sourced from all the declarations.”

SNP MSP George Adam said: “The Tory dark money scandal is a running embarrassment for the party, and they’re doing themselves no favours in trying to hide from scrutiny.

“David Mundell has repeatedly tried to deny his links to the Scottish Unionist Association Trust. Now it seems they helped bankroll his election campaign.

“We’re talking about one of the most senior Tories in Scotland here. He should be open and honest over where this money came from.

“Transparency over party finances is absolutely essential in any healthy democracy. The public have the right to know who helped put their politicians into office.”

The Scottish Conservatives said all SUAT donations to the party and all election spending had been properly and fully reported to the Electoral Commission in line with the law.

Mairi McAllan, the SNP’s candidate in Mundell’s constituency at the 2017 election, tweeted: “It’s very difficult to counter an opponent who uses dark money to secure their victory.”

Last month, the SUAT were forced to come out of the shadows to reveal details of their trustees and sources of their money.

An investigation by The Ferret revealed they had donated £318,876.66 to the Tories between April 9, 2001, and February 28 this year.

Because the SUAT is not registered with Companies House, the Financial Conduct Authority, or OSCR – Scotland’s charity watchdog – there was no public information about who currently manages the organisation, and no public accounts to indicate donors or assets.

SNP Westminster leader Ian Blackford brought up the SUAT in the House of Commons in June.

Blackford was almost drowned out by braying Tory MPs as he accused the party of buying democracy.

He said the Tories were “systematically shielding their donations from public scrutiny.”

Shortly after the exchange, the SUAT released a statement through the PR company of trustee Peter Duncan, a former Tory MP. It revealed the trust was formed in 1968 from “assets of the (then) Scottish Unionist Association, primarily sales of property assets.”

SUAT added that those assets had been invested and the proceeds were now “available to further the aims of the Scottish Conservative and Unionist Party.

It insisted: “All UK taxation liabilities have been and continue to be met in full.”

As well as Miller-Bakewell and Peter Duncan, trustees included Kim Donald, Patricia McPhee, Sheila Fulton, John Duncan, and Frank Spencer-Nairn.

Last week, Peter Duncan announced he would be standing down from SUAT because he wanted “more separation” between its work and his role as a lobbyist.

He said the Trust had funded the nearly £319,000 given to Tory campaigns over 17 years from the “historic proceeds of raffles and tombolas”.

“The suggestion that this is in some way dark money is a bit like suggesting the WI is some KGB front organisation. This is historic proceeds of tombolas and raffles throughout the west of Scotland going back 50 years.”