Gina Rinehart used tactics bordering on intimidation and sought to wield her influential connections in the battle against her two eldest children over the multibillion-dollar family trust.

If this was how the mining magnate was prepared to act towards her children, Justice Paul Brereton wondered how much further she’d go when faced with a corporate entity overseeing the trust, estimated to be worth up to $5 billion.

With this in mind, he ordered control of the trust be handed over to her eldest daughter, Bianca Rinehart.

“I have never seen such pressure exerted, so persistently, on a litigant, as has been apparent in this case,” Justice Brereton said on Thursday in the Supreme Court.

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It was a hard-fought victory for her two eldest children, John Hancock and Bianca, on the day their mother was again named Australia’s wealthiest person – topping the 2015 BRW Rich list for the fifth consecutive year with a worth of $14 billion.

Mr Hancock and Bianca – along with their sister Hope Welker – launched legal action against their mother in September 2011 on the back of a letter she sent them three days before their youngest sister, Ginia Rinehart, turned 25 and the family trust was due to vest.

In the September 3 message, Mrs Rinehart said if the trust, which listed her children as beneficiaries, vested they would become liable to pay capital gains trust and they would become bankrupt.

These consequences could only be avoided by extending the vesting date, she said.

But as documents obtained during the course of the litigation have revealed, Justice Brereton said Mrs Rinehart and her chief financial officer, Jay Newby, had received no such tax advice.

Moreover, he found the dispatch of the letter was “intentionally delayed” so that the children only had one business day to obtain professional advice.

In the legal battle that followed, Justice Brereton found “Mrs Rinehart has repeatedly, directly, or through her lawyers, or through other influential connections” sought to deter her children from prosecuting by employing measures “some of which closely approach intimidation”.

He pointed to an email Senator Barnaby Joyce sent to Ms Welker on September 11, 2011 to try and dissuade her from litigation.

Then in February 2012, Justice Brereton said Mrs Rinehart threatened to withdraw ransom insurance intended for the protection of Bianca and her young son.

In March 2013, she procured Ms Welker’s withdrawal from the claim by making her loans of about $45 million.

Even after Mrs Rinehart relinquished her role as trustee in October 2013, Justice Brereton found she had “demonstrated that she is prepared to go to extraordinary lengths to retain control, directly or indirectly, of the trust, and that she is capable of exerting enormous pressure, and great influence, to do so, and to secure the appointment of a trustee acceptable to her”.

He rejected moves to appoint various licensed trustee companies to manage the fund.

The position of trustee, is in truth, a “poisoned chalice”, Justice Brereton said.

He found Bianca was the best person for the job.

The parties will return to court for a later date to discuss costs.

-AAP