~The British government has urged the U.S. Supreme Court to review appeals court rulings against BP Plc (BP.L) over a 2010 Gulf of Mexico oil spill that produced one of the largest class actions in American history.

In a friend of court brief, the UK government said lower court rulings raise grave international concerns by undermining confidence in the "vigorous and fair resolution of disputes."

The filing said BP, which has "gone to great lengths to restore the Gulf Coast", was now being required to pay large sums to others who were not injured by the Deepwater Horizon oil spill.

The London-based oil major is appealing lower court decisions within the last year that it believes wrongly require it to compensate claimants who suffered no injuries from the spill.

The British government said treatment meted out to BP undermined the fairness and trust necessary for international commerce.

The United States and Britain conduct more than $200 billion in trade each year, and UK businesses are responsible for 17 percent of all foreign direct investment in the United States, according to the filing.

In a separate statement, BP said the government's petition emphasizes the importance of fair and consistent application of law.

BP argued that the Fifth Circuit's decisions, if allowed to stand, will fundamentally alter class action law and discourage companies from settling complex cases.

It also said the decisions will likely discourage companies from investing in the United States "if companies are exposed to liability for losses they did not cause.

Separately, a Louisiana court ruled last week that BP was "grossly negligent" and "reckless" in the spill, a move that could add nearly $18 billion in fines to more than $42 billion in charges.

BP last week said it would appeal that ruling.