Morgan Lewis & Bockius is advising BP as it faces a $28m (£17.91m) fine in a US court after a judge decided that it had rigged natural gas markets in 2008.

The Philadelphia firm acted for the oil company in a case heard by Federal Energy Regulatory Commission (FERC) administrative law judge Carmen Cintron, last week.

The case centres on the accusation that BP traders manipulated natural gas markets in the aftermath of Hurricane Ike between September 18 2008 and November 30 2008.

In her judgment, Judge Cintron said: "The evidence shows that BP engaged in a scheme to defraud."

Morgan Lewis' team includes energy regulatory partner Mark Haskell, litigation of counsel George Billinson and regulatory partner Brett Snyder.

Also appearing were BP managing counsel of global litigation Timothy Moorehead and senior counsel of BP Betsy Carr.

The decision is not final and will be subject to a review by FERC's commission.

A BP spokesperson said: "We strongly disagree with this decision by the FERC Administrative Law Judge. As BP demonstrated at the hearing, the FERC enforcement staff's allegations are entirely without merit."

He said that BP intended to appeal the decision.

BP faced extensive litigation costs in the US following the Deepwater Horizon oil spill in the Gulf of Mexico in 2010. In February this year the oil company estimated that its costs from the incident had reached $26.8bn (£17.7bn).

Law firms including Kirkland & Ellis, Gibson Dunn & Crutcher, Dentons and Arnold & Porter have been advising BP in relation to litigation stemming from the oil spill.