A US judge has voided a legal agreement between President Donald Trump and federal agencies that granted him immunity from tax audits and allowed his administration to create a since-abandoned $1.8bn (£1.3bn) “anti-weaponisation” fund.

The fund, intended to compensate individuals claiming they were unfairly targeted by the government, was unveiled in May in exchange for Trump dropping his personal $10bn lawsuit against the Internal Revenue Service (IRS).

But on Monday, US District Judge Kathleen Williams said the suit was filed for an improper purpose.

She also referred a Trump lawyer to state authorities to determine whether ethics rules were violated and disciplinary action required.