LONDON (AP) — Britain’s main opposition party said Thursday it was deeply concerned by new allegations about a controversial personal friendship that are heaping pressure on the country’s defense minister.

A government inquiry is scrutinizing the role of Defense Secretary Liam Fox’s friend Adam Werritty, who had access to the minister’s schedule, arranged unofficial meetings and has been present on 18 overseas trips since May 2010.

Lawmaker Jim Murphy, the opposition Labour Party’s defense spokesman, said he was deeply concerned over allegations that a circle of business executives offered Werritty funding to act as an unofficial adviser.

The BBC, without citing its sources, reported that a number of wealthy businessmen had paid for Werritty to act as nonofficial aide to Fox to promote their interests, and to build support for a more hawkish foreign policy line.

Fox’s office has insisted that Werritty, who has been questioned by the government inquiry, had no official role.

Murphy said it would be a clear breach of rules on ministerial conduct if Werritty was being paid to act as a rogue adviser, operating outside usual government channels.

Fox, who canceled a planned news conference Wednesday during a visit to France, said he would not be distracted from his role, amid the continuing NATO-led air campaign in Libya.

"I’m continuing to do what is needed at the moment, which is that the defense secretary focuses on defense issues," he told reporters, before a National Security Council meeting on Libya.