Treasury pays Deloitte more than £6 million to help defend lawsuit from Iranian finance house Mellat

The Treasury has paid Deloitte more than £6 million to help defend a multi-billion lawsuit from Iranian finance house Mellat despite the bank also being a client of the accounting giant.

Tehran’s Bank Mellat was slapped with financial sanctions by the Treasury under the Counter-Terrorism Act due to its apparent involvement in funding the Iran nuclear programme.

The bank sued, successfully claiming in the Supreme Court that the sanctions were unlawful.

It is now seeking damages of $4 billion (£2.9 billion) in what is the biggest claim ever taken against the UK Treasury.

The Deloitte contract, awarded in March 2016, is for forensic accounting work and was uncovered by public tenders researcher Tussell.

It is among the biggest handed by Whitehall to a single firm for accountancy.

However, Deloitte was also acting as auditor of Bank Mellat’s large Turkish operation at the time, signing off its accounts as recently as last April.

It denied this represented a conflict of interest, saying it informed the Treasury and that it no longer acts for Bank Mellat.

Mellat’s lawyers Zaiwalla & Co said the case has been relisted for June 2019.