HM Revenue & Customs (HMRC) has issued a thinly veiled warning to ­Rangers ahead of the taxman's appeal against the oldco company's 'big tax case' win after a Scottish firm settled a £7 million bill for tax avoidance.

Aberdeen Asset Management has lost a lengthy court battle over a scheme used a decade ago which paid £31m of bonuses to seven senior employees, including its founder and chief executive Martin Gilbert.

In a statement, HMRC said: "This decision will be a big help when we come to argue other cases that are currently in the courts."

The oldco Rangers, which was ­liquidated last year, won a £36m ­avoidance case on a 2-1 majority verdict in the first tier tax tribunal in November last year. The appeal is due to go to an upper tax tribunal in the new year.

However, Aberdeen Asset Management has had to settle a bill for tax avoidance in a case with similarities to the oldco Rangers' legal battle.

A tax expert said: "It can be inferred from the judges' comments they strongly concur with the dissenting opinion in the Rangers case. I think they have half an eye on the Rangers case."

The Herald revealed in 2011 that the lower tax tribunal had ruled against Aberdeen's "discounted options scheme", a variant of the employee benefits trust used by Rangers and other employers until new legislation forced their closure.

Aberdeen had avoided £7m of tax and national insurance due on bonuses, including £1.2m in respect of Mr Gilbert, by setting up what the judges called "money-box companies."

HMRC has now proved that bonuses should be treated as cash payments liable for PAYE and National Insurance paid by the company.

In a statement, Aberdeen Asset Management said: "We are disappointed the court's decision has gone against us, but we welcome the fact that we can now draw a line under this issue. All amounts assessed by HMRC have previously been paid and the decision has no further financial impact on the group."

Meanwhile, Prime Minister David Cameron is expected to make an announcement today on tax dodging, saying that a register of the true owners of shadowy shell companies will be made public as part of the fight against tax avoidance.