LAGOS, Aug 16 (Reuters) – A judge in London said on Friday he would grant a firm called Process and Industrial Developments Ltd (P&ID) the right to seek to seize some $9 billion in assets from the Nigerian government over an aborted gas project.

The company was awarded $6.6 billion in an arbitration decision over a failed project to build a gas processing plant in the southern Nigerian city of Calabar. With interest payments, the sum now tops $9 billion – some 20% of Nigeria’s foreign reserves

The judge’s decision, issued on Friday, converts the arbitration award to a legal judgement, which would allow P&ID to try to seize international assets.

Lawyers representing the Nigerian government argued the award should not be enforced because England was not the correct place for the case, and even if it were, the amount awarded was “manifestly excessive.”

Mr Justice Butcher of the Commercial Court rejected these arguments and said he would “receive submissions from the parties as to the precise form of order appropriate.”

A spokesman for Nigeria’s President Muhammadu Buhari directed requests for comment to the Ministry of Justice, which did not immediately respond. A spokeswoman for the law firm representing the Nigerian government in London did not immediately provide a comment on the ruling.

“P&ID is committed to vigorously enforcing its rights, and we intend to begin the process of seizing Nigerian assets in order to satisfy this award as soon as possible,” said Andrew Stafford, Q.C. of Kobre & Kim, which represents P&ID.

The case involves a 2010 deal in which the Nigerian government agreed to supply gas to a processing plant in Calabar that P&ID – a firm founded by two Irish businessmen specifically for the project – would build and run.

In 2012, P&ID took the government to arbitration over the failure of the deal and won the award, which was based on what it could have earned during the 20-year agreement.

Stafford said that with accrued interest, the award now tops $9.6 billion.

Legal experts told Reuters previously that assets used for diplomatic purposes – such as the Nigerian High Commission building in central London – are not eligible for seizure, but commercial assets are.

(Reporting by Libby George, additional reporting by Felix Onuah and Camillus Eboh in Abuja; Editing by Mark Potter)