(Reuters) – Nigeria on Monday won its bid to overturn an $11 billion damages bill for a collapsed gas processing project it said was procured by a concerted campaign of bribery.

The West African country was on the hook for the sum – representing around a third of its foreign exchange reserves – after a little-known British Virgin Islands-based company took Nigeria to arbitration over the deal.

Process & Industrial Developments (P&ID) was awarded a 20-year contract in 2010, to construct and operate a gas processing plant in southern Nigeria, as part of a wider plan to exploit Nigeria’s abundant reserves of gas.

After the deal collapsed, P&ID took Nigeria to arbitration in London and in 2017 was awarded $6.6 billion for lost profits – a sum which has swelled with interest to over $11 billion, representing ten times the country’s 2019 health budget.

However, Nigeria’s lawyers say the country was the victim of “a campaign of bribery and deception” by P&ID, which they say paid bribes to senior officials to obtain the contract and then corrupted the country’s lawyers to obtain confidential documents during the arbitration.

P&ID denied that it procured the contract through bribery or that it corrupted Nigeria’s legal team during the arbitration, blaming the failure of the gas deal and the country’s arbitration defeat on institutional incompetence.

Judge Robin Knowles allowed Nigeria’s challenge in a written ruling on Monday.

“I have not accepted all of Nigeria’s allegations,” the judge said in his ruling.

But he added that the arbitration awards “were obtained by fraud and the awards were, and the way in which they were procured was, contrary to public policy”.