LONDON- The British government has settled a 1.25 billion pound ($1.6 billion) damages claim brought by Iran's largest private bank in an 11th-hour, out-of-court deal following a dispute over sanctions and alleged links to Tehran's nuclear programme.

Bank Mellat, which is 20% owned by the Iranian government and 80% privately held, said on Tuesday the legal row had been resolved for an undisclosed sum on the first day of a trial to assess its damages at London's High Court.

That comes six years after the UK Supreme Court ruled that sanctions imposed on the bank in 2009 were unlawful and that the government had been "irrational" and "disproportionate". It referred the case back to the High Court.

Bank Mellat had argued that sanctions had damaged its reputation and goodwill in Britain and internationally, and caused significant loss.

The government's Treasury department issued a brief statement, saying: "Bank Mellat's claims have been concluded on terms confidential to the parties."

Sarosh Zaiwalla, a lawyer and founder of London-based Zaiwalla & Co, the law firm representing Bank Mellat, said the case spoke volumes for the independence of the British judiciary.

($1 = 0.7980 pounds)

(Reporting by Kirstin Ridley; Editing by Jan Harvey) ((kirstin.ridley@thomsonreuters.com; +44 (0) 207 542 7987; Reuters Messaging: kirstin.ridley.reuters.com@reuters.net))