THE LIQUIDATORS of Rangers oldco have formally launched a legal challenge against the taxman's victory in the long-running 'Big Tax Case' to the highest appeal court in the land.

BDO has made an application to the Court of Session to be granted leave to make a final appeal to the Supreme Court.

The move to take the matter to the Supreme Court was favoured, and contact has already been made with former Rangers owner David Murray over the case.

The move makes the liquidators the prime movers in the challenge of the decision by three judges at the Court of Session in Edinburgh that Rangers' use of Employee Benefit Trusts (EBTs) broke tax rules.

According to the Courts Reform (Scotland) Act 2014, from September 22, any party wishing to overturn decisions of the Inner House of the Court of Session, Scotland's upper appeal court must now ask that court for permission before seeking to bring a further appeal to the UK Supreme Court.

But if the inner house refuses permission, BDO could then ask the Supreme Court directly for permission to appeal. The permission will normally only be given if the appeal raises a point of "general public importance".

Previously, appellants from Scotland had an automatic right of appeal in civil matters, provided that two advocates certified an appeal as reasonable.

Announcing the decision, BDO said: "Following discussions with the company's legal advisers and the liquidation committee, the joint liquidators have filed an application seeking leave to appeal the Inner House of the Court of Session decision in respect of the EBT case.

"If the company successfully obtains leave to appeal, the appeal will be heard in the Supreme Court in London.

"The joint liquidators are not in a position at this stage to make any further comment in respect of the appeal."

The big tax case decision brought the debate over "tainted titles" into the public arena again with some calling for the club to be stripped of titles and competitions won in the years the EBTs were used claiming Rangers had obtained an unfair sporting advantage.

But an appeal would put any question of further sporting sanctions on the back burner.

Rangers used the scheme from 2001 until 2010 to give millions of pounds of tax-free loans to players and other staff.

The Court of Session judges agreed with HM Revenue and Customs which argued that the use of EBTs were a way of paying players, managers and other staff and should be taxable like all salaries. Former owner Sir David Murray had twice successfully argued at tax tribunals that they were loans and therefore exempt.

The appeal judges, Lord Carloway, sitting with Lord Menzies and Lord Drummond Young ruled that if income was derived from an employee's services, in their capacity as an employee, it was an emolument or earnings and "thus assessable to income tax".

The argument expected to be put forward by way of challenge is that the application of common sense over the substance of the law, was wrong.

In the financial year 2014/15, the Supreme Court received ten appeals or references from Scotland 'as of right', and received five applications for permission to appeal where the appellant needed to seek it - typically in relation to 'devolution issues'.

In 2013/14, the figures were 13 appeals as of right, and three applications for permission to appeal.

Liquidators have previously confirmed that £72m of the £94.4m owed to HMRC relies on the taxman's claim that Rangers was liable for its use of EBTs.

Many believe the threat of the potentially crippling tax case led to the bank insisting the club debts were cleared, resulting in a disastrous sale to venture capitalist Craig Whyte, a subsequent liquidation, and the decision to put Rangers in the Third Division.

A taxman victory meant that the maximum amount of debt potentially left by the oldco would remain at the £168.8 million and would undoubtedly result in minimal payouts to other creditors.

However the extra costs from a protracted court case will further reduce the creditors pot which has stood at £18 million.