Britain's defence minister faced renewed pressure Thursday over claims that rich backers paid for the best man at his wedding, who is not a government official, to travel the globe with him.

Liam Fox again rejected calls to resign over his links to his close friend Adam Werritty, who posed as the minister's advisor and accompanied him on 18 overseas visits to countries including Sri Lanka and Dubai.

The BBC reported that 34-year-old Werritty was being bankrolled by several wealthy private clients who shared Fox's private foreign policy views, which are said to be more eurosceptic and pro-US than the British government's.

The defence spokesman for the opposition Labour party, Jim Murphy, said the claims "blow a hole" in Fox's defence and that there would be a clear breach of ministerial guidelines if Werritty was being paid as an unofficial adviser.

It also emerged Friday that Fox and Werritty attended a dinner in Washington with leading names from the defence industry, which was not declared by the defence ministry.

The function was attended by US defence industry lobbyists and military officials, the Daily Telegraph reported.

A spokesman for Fox said that he had been attending the event in a "private capacity" during a spell of annual leave.

Fox, 50, said on Thursday he was concentrating on his job, especially as the conflict in Libya appeared to be nearing its end.

"I'm continuing to do what is needed at the moment which is that the defence secretary focuses on defence issues," he told reporters at the Ministry of Defence (MoD) after attending a national security council meeting.

"I think we're getting very close to the fall of Sirte which I think may bring the Libyan conflict to a close, and that is what I have to focus all my attention on."

He was sitting in parliament alongside Foreign Secretary William Hague on Thursday as Hague made a statement on the situation in the Middle East.

But government sources said civil servants were going to interview Werritty for a second time this week as part of an investigation into Fox's conduct ordered by Prime Minister David Cameron earlier this week.

"The earlier conversation was more about establishing some of the basics. This (new interview) will be a lot more about understanding some of the issues," one source told AFP.

Werritty would be reinterviewed on Thursday or Friday, the source said.

British media carried a string of stories about the controversy on Thursday, especially about the tangled web of businessmen and lobbyists, many of them with links to Israel and Dubai, said to surround Fox and Werritty.