THE head of a fundraising operation which has given the Scottish Conservatives more than £350,000 has been named on a government list of "tax cheats".

HM Revenue and Customs last week added Robert Miller-Bakewell, the chairman of the Scottish Unionist Association Trust (SUAT), to its public register of "deliberate tax defaulters".

If followed Mr Miller-Bakewell, whose brother Archie is private secretary to the Duke of Edinburgh, owing the authorities almost £200,000 in taxes and penalties.

The notice showed he recently incurred penalties of £60,512 on capital gains tax of £138,313, with the "period of default" between April 2012 and April 2015.

Mr Miller-Bakewell, of Melrose in Roxburghshire, has been the chairman of the SUAT since 2012.

He told The Herald his tax affairs were up to date and added he had "no outstanding liabilities" to HMRC.

But he also declined to say if he had paid the taxman or disputed owing the sums.

The SNP called on Scottish Conservatives leader Ruth Davidson to be "totally transparent" about her party's funding.

READ MORE: SNP call for watchdog to check David Mundell 'dark money' funding

HMRC only names tax defaulters whose penalties became final within the last 12 months, and after all appeal routes have been exhausted.

When HMRC first published the list in 2013, it described those it named as "tax cheats".

Then Exchequer Secretary to the Treasury David Gauke said: "The publication of these names sends a clear signal that cheating on tax is wrong and reassures people who pay their taxes – the vast majority – that there are consequences for those who refuse to tell HMRC about their full liability."

According to the Electoral Commission, the SUAT has given Scottish Tory branches £354,156 in small donations since 2001, including money to help pay for Scottish Secretary David Mundell's campaign manager.

Around £160,000 of the donations were made after Mr Miller-Bakewell became its chair.

READ MORE: Secret Tory funders break cover after May challenged

Because it does not publish accounts or detail its revenue, the SUAT has been accused of being a source of so-called "dark money", or untraceable political funding.

It was only after SNP Westminster leader Ian Blackford raised the outfit at Prime Minister's Questions last year that it named its trustees and chair.

The Electoral Commission is currently investigating its donor status.

Mr Miller-Bakewell, 66, is a long-standing Tory activist in the Borders, and served for many years as an office bearer on the Scottish Borders Conservative and Unionist Association.

He was Borders Association chair and treasurer in 2014 and 2015, when the SUAT began funding Mr Mundell's campaign manager.

Ahead of the 2015 general election, he was one of a number who formally nominated Tory candidate John Lamont, now the MP for Berwickshire, Roxburgh and Selkirk.

READ MORE: David Mundell's election campaign financed by Tory 'dark money' fund

Mr Miller-Bakewell is also chairman of the trustees of the Scottish Conservative and Unionist Association Trust, a small charity, and a director of Kelso Races Ltd.

The tax defaulters list names firms and individuals who have incurred a penalty for having "either deliberately provided one of more inaccurate documents to HMRC, deliberately failed to comply with an HMRC obligation, or committed a VAT or excise wrongdoing".

People are included if their "deliberate acts have resulted in HMRC establishing an additional amount of tax of more than £25,000".

SNP MP Pete Wishart said: "These are remarkable revelations about the chair of the SUAT.

"It's high time Ruth Davidson was totally transparent about who's funding her party."

Mr Miller-Bakewell said: "My tax affairs are up-to-date. I have no outstanding liabilities to HMRC."

A Scottish Tory spokesman said: "These are private matters for Mr Miller-Bakewell to sort out."

An HMRC spokesperson said: "HMRC is committed to making sure people pay the tax they owe. For the minority who refuse to pay, HMRC has a range of tools available."

The Electoral Commission confirmed its investigation into the SUAT remains ongoing.