UK trading firm Prax, which has a fuel distribution arm under the name Harvest Energy, completed the acquisition of the 110,000 barrel-per-day refinery in Lincolnshire from Total on Monday.

"This arrangement is an important step in the group's plans for the long-term growth of the refinery and it will pave the way to further strengthen our long-term relationship with Trafigura," Prax Chief Executive Sanjeev Kumar said.

Other details of the transaction were confidential, the statement said. The refinery purchase was announced in July last year.

Prax sought financing for the deal from Australian bank Macquarie and separately Geneva-based Mercuria Energy Trading, according to a court document filed by Mercuria in London in January.

The filing was part of a $4 million lawsuit against Prax's parent company State Oil Ltd, which alleges that the firm was in breach of its contract with Mercuria for the potential financing of the refinery.

(Reporting by Julia Payne; Editing by David Evans and Jan Harvey)

By Julia Payne