A private jet company formerly owned by Celtic’s biggest shareholder, Dermot Desmond, has been accused of using an “aggressive” offshore tax avoidance scheme by a leading QC.

The Irish billionaire owned Swiss-based Execujet for eight years until he sold it in 2015.

Emails from the leaked Paradise Papers reveal Execujet asked a law firm to open an Isle of M

READ MORE: 63 not out - but Celtic manager Brendan Rodgers wants more of the samean company in 2012 which allowed Swiss taxes to be avoided.

More than 13 million documents have been leaked from the offshore law firm Appleby.

It was revealed that a number of politicians, celebrities, corporate giants and business leaders to secretive overseas arrangements.

Yesterday, it was emerged: - Apple avoided a 2013 crackdown on its controversial Irish tax practices by actively shopping around for a tax haven.

- F1 world champion Lewis Hamilton avoided tax on his £16.5m luxury jet.

- Three stars of the BBC sitcom Mrs Brown’s Boys, Patrick Houlihan and Martin and Fiona Delany, are said to have diverted more than £2m into an offshore tax-avoidance scheme.

BBC Scotland’s investigations team, which was involved in the global media leak, uncovered that Mr Desmond’s company Execujet may have avoided up to $1.3m (£1m) in Swiss taxes over three years.

The documents revealed that Appleby staff set up a company in the Isle of Man, called ExecuJet (IOM) Limited, as its primary insured office.

This led to the avoidance of a five per cent stamp duty levy on an insurance premium and tax on a “brokerage” fee from its insurers.

The offshore structure implemented by Appleby is legal but tax expert Philip Simpson QC told the BBC it appeared to be “an aggressive avoidance arrangement”.

READ MORE: 63 not out - but Celtic manager Brendan Rodgers wants more of the same

He said that the Isle of Man company seemed to be controlled from Switzerland, which could make it liable for taxes there.

Mr Desmond strongly denies his former company had avoided tax.

He told the BBC it was “tax and regulatory compliant in all jurisdictions it operated in”.

Questioned outside Celtic Park before last week’s Bayern Munich Champions League tie, Mr Desmond said it was “absolutely wrong” to say Execujet was a tax avoidance vehicle.

Pressed further by the BBC’s reporter, he replied: “I’m not duty bound to educate you in how we run our affairs.

“Every company in the Isle of Man is not for avoidance of tax.” He declined to give further details for reasons of confidentiality, but later wrote to the BBC .

In the letter, Mr Desmond said: “There are good operational reasons for having a presence in the Isle of Man and many international companies do so. Similarly, my aircraft arrangements and my shareholding in Rietumu are fully tax and regulatory compliant. Any allegation to the contrary is a lie.”

READ MORE: 63 not out - but Celtic manager Brendan Rodgers wants more of the same

Execujet said: "ExecuJet, a private company, operates in many countries around the world.

"It is very important to ExecuJet that it is compliant with all tax rules globally.

"Several years ago, ExecuJet chose the Isle of Man as it is a centre for insurance and re-insurance companies providing an attractive financial and fiscal environment.

"However, for some time now, ExecuJet IOM has not been required and is therefore no longer used."

Earlier this year, the Herald revealed that Latvian-based bank, Rietumu Banka - which is part owned by Mr Desmond - was fined for facilitating industrial-scale tax evasion in France. Mr Desmond was not named in court proceedings and there was no suggestion the billionaire, as a shareholder or board member, had any knowledge or involvement in any wrongdoing.