UPDATE 1-Ukraine court says PrivatBank nationalisation violated the law

A Kiev court ruled on Thursday that the government's decision in 2016 to nationalise the country's biggest lender, PrivatBank, violated the law.

The central bank said it would appeal the ruling and that it was impossible to reverse the nationalisation. The finance ministry also said it would appeal the decision. The court ruling could benefit Ihor Kolomoisky, a powerful tycoon who owned PrivatBank at the time it was nationalised and is fighting multiple court cases against the decision.

Kolomoisky is also a backer of Volodymyr Zelenskiy, a comedian and frontrunner to become the country's next president at an election run-off on Sunday. The government wrested PrivatBank from Kolomoisky in 2016 and then shored up the lender with billions of dollars. The government wants to recover money it says was siphoned out while Kolomoisky owned it. Kolomoisky denies any wrongdoing and says the bank was forcibly nationalised without proper justification.

"The court ruling has yet to come into effect and will be appealed by the NBU (National Bank of Ukraine)," Viktor Hryhorchuk, head of litigation at the central bank's Legal Department, said in a statement. Lawsuits challenging the nationalisation of PrivatBank "deal irreversible damage to Ukraine's international image," the central bank said in the same statement. (Reporting by Natalia Zinets and Pavel Polityuk; writing by Matthias Williams; Editing by Susan Fenton)