Watch the Rangers Big Tax Case LIVE from the Supreme Court

A live feed of the case is being broadcast by the Crown through the Supreme Court website.

The move by BDO makes them 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.

It is understood they have had advice from former Rangers owner David Murray over the case.

Justices sitting in the case are Lord Neuberger, Lady Hale, Lord Carnwath Lord Reed, and Lord Hodge.

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.

It also has a major bearing on the amount of money given to creditors from the liquidation of oldco, The Rangers Football Club Plc.

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

After the latest tax case judgement the Scottish Professional Football League held an emergency meeting at Hampden Park to discuss whether it means sporting sanctions were either justified or workable. BDO were granted permission to go to the UK Supreme Court following a hearing at Edinburgh's Court of Session on March 7.

The appeal put any question of further sporting sanctions on the back burner.

The appeals surrounds judges agreeing with HM Revenue and Customs 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".

RANGERS BIG TAX CASE AT THE SUPREME COURT - LIVE

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.

The call for the Supreme Court appeal came before Lord Menzies Lord Drummond Young, and Lord Carloway, one of Scotland's most senior judges, all of whom originally found in favour of HM Revenue and Customs (HMRC) in November.

They agreed that an appeal against their judgment should now be heard at the Supreme Court.

Lord Carloway, the Lord Justice Clerk, said the judges had allowed the case to go to the Supreme Court because of the implications that it had for similar cases.

HMRC are thought to be pursuing a number of football clubs over claims that they also used employee benefit trusts inappropriately.

Lord Carloway said: "The court is of the of the view that there is an arguable point of law of public interest which should allow the appeal to the UK Supreme Court to proceed.

"There are significant issues in this case which may apply to other similar situations."

The original November judgment meant the taxman, in one of the biggest tax claims it has ever pursued, won its claim Rangers oldco were liable for a £46.2 million bill over the use of EBTs.

A group of Murray firms including parent company Murray Group Holdings Ltd, had originally defended the claims, however the courts have been told they have since gone into liquidation leaving BDO and the Rangers oldco as the only opponents.

Her Majesty’s Revenue and Customs (HRMC) lost a first-tier tax tribunal and a subsequent 2014 appeal over the payments made by Mr Murray's group of companies.

At the time, the tax authority had argued that payments made to players and other employees should be taxable but the Murray Group, which formerly owned Rangers, successfully argued they were loans.

The November judgment overturned a decision of upper tier judge Lord Doherty in largely supporting a first-tier tax tribunal (FTT) decision in favour of the Murray Group.

But 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 earnings and "thus assessable to income tax".

Court reform rules which came in in September, 2015 meant that an automatic right of appeal to the UK Supreme Court over Court of Session decisions ceased to exist. Leave to appeal had to be sought by the Court of Session in the first instance.

According to the Courts Reform (Scotland) Act 2014, it will only be granted if the court "considers that the appeal raises an arguable point of law of general public importance which ought to be considered by the Supreme Court".

Liquidators have previously confirmed that £72m of the £94.4m owed to HMRC relies on the taxman's claim that Rangers oldco 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 of £18 million were cleared, resulting in its sale, a subsequent liquidation, and the decision to admit Rangers into the bottom tier of the Scottish league ladder.

RANGERS BIG TAX CASE AT THE SUPREME COURT - LIVE