CHIEF Secretary to the Treasury Danny Alexander has been urged to return a £50,000 donation from a self-confessed tax avoider.

It emerged last week that the Liberal Democrat MP, who is building a fighting fund to defend his Inverness seat in May's General Election, accepted the money from Orion engineering boss Alan Savage.

His parliamentary register of interests records two £25,000 donations from Savage's Inverness-based Orion Engineering Services Ltd.

However, Alexander is now under fire given his tough line on people paying all of the tax they owe and Savage's admitted tax avoidance.

Last year, Alexander told the BBC's The Andrew Marr Show he was "livid" at companies and individuals "avoiding paying the proper amount of tax".

But in a 2011 court case, Savage, who went on to give £300,000 to the pro-Union Better Together campaign in the referendum, admitted he employed a former girlfriend in spite of her doing no work in order to save money on tax - a wheeze that the Inland Revenue subsequently brought to an end.

Savage admitted it had been wrong to claim tax allowances for someone who did no work, and said he could not justify it to the authorities.

The SNP accused Alexander of double standards.

Highlands and Islands MSP Dave Thompson said: "As a Treasury Chief Secretary, Danny Alexander should be more careful to practice what he preaches. He claims to be 'livid' about companies and individuals who don't pay their proper share of tax, yet he has just accepted a big campaign donation from someone who by his own admission was avoiding tax owed to the Inland Revenue.

"For the sake of the credibility of his anti-tax avoidance message, Danny Alexander should consider returning this money."

In October 2013, Alexander emphatically condemned those not paying their proper share of tax.

He said: "People are rightly livid about companies and individuals avoiding paying the proper amount of tax. I'm livid about that. It's something which is not acceptable at any time, but particularly at a time when we are going through tough spending choices. Everybody needs to pay their fair share."

Yet in a high-profile court case, Savage admitted he had once not done so. The millionaire, a former chairman of Inverness Caledonian Thistle football club, revealed the fact when he was sued by his ex-­girlfriend Julie Zelent.

Zelent claimed for loss of earnings, employment benefits and pensions rights.

In December 2011 at Inverness Sheriff Court, during five hours of questioning, Savage, 64, told the court he employed Zelent to take advantage of a lower tax rate.

She was paid an annual salary of £50,000 through an Orion company during the first part of their ­relationship from November 2006 and August 2007.

Savage told the court: "I employed her for two reasons. Firstly, she asked me if she could get a wage so she could ­somehow keep up payments on her mortgage in Bedfordshire. It was a way of getting money at a lesser rate of tax. It was using taxable allowances. It suited both of us."

Zelent's advocate Andrew Hajducki QC, then asked: "Isn't it wrong for you then to claim ­taxable allowance for an employee who didn't do anything?"

Savage replied: "Yes."

Savage added that the Inland Revenue investigated the issue after reading about the case in the press.

Hajducki said: "Did the Inland Revenue ask you why you were paying an employee who doesn't do a job? What was your answer?"

Savage replied: "I did not have a good answer. They made me pay the tax."

After the hearing, Sheriff ­Margaret Neilson threw out Zelent's case, describing her as "lacking in any credibility whatsoever".

Neilson said there was no basis to find Savage "anything but credible and reliable".

A LibDem spokesperson said: "This donation has been reported with full transparency and accepted by the electoral commission.

"Alan Savage has invested in the Highlands and created a hugely successful business and hundreds of jobs. Nationalists should stop attacking people who help to make the Scottish economy a success - Danny is proud that such people are supporting him.'

A spokesman for Orion said Savage was unavailable for comment.