A judge has ruled that BP is not permitted access to 21 confidential US government documents.

The US government claimed that the communications between the White House and other officials, which included emails found in ediscovery processes, were privileged and should not be handed over to BP.

These documents relate to policy deliberations during the Deepwater Horizon disaster and BP claimed they may be relevant to the court case in which the US is suing the oil giant for safety failings.

"BP's need for the documents does not outweigh the interest of the U.S. in protecting the deliberative process," said US magistrate Judge Sally Shushan. "BP’s challenges to all 21 documents will be denied."

The oil giant had hoped that the emails would be submitted as it sought to defend itself over US government claims.

However, the documents are protected under rules that prevent government policy discussions from being made public.