Questions over Liam Fox's US fund-raiser engagement

Defence Secretary Liam Fox and lobbyist Adam Werritty attended a 500 dollar-a-head dinner in Washington with senior figures from the defence industry which has not been declared by the Ministry of Defence, it was reported.

The Daily Telegraph claimed that Dr Fox and Mr Werritty were both guests at the £318-per-person fund-raising dinner last year at the Mandarin Oriental hotel attended by US defence industry lobbyists and military officials.

The event did not appear on the list of 18 occasions where Dr Fox and Mr Werritty both attended overseas engagements released earlier this week by the MoD.

A spokesman for Dr Fox said that he had been attending the event in a "private capacity" during a period of annual leave and that the visit did not involve the use of taxpayers' money.

However, the disclosure is likely to lead to claims he has still not come clean about the full extent of his contacts with Mr Werritty, despite admitting to meeting him 40 times since coming to office last year - including twice on family holidays overseas.

The event in Washington was organised by US Atlantic Bridge - the sister organisation of the now defunct charity which Mr Werritty used to head in London.

The organisation's chief executive Amanda Bowman told the Telegraph: "Adam was with him (Dr Fox). He showed up that night because he was travelling with Liam.

"He was Liam's most trusted friend, and was at one of the top tables talking to other guests."

Other guests at the dinner were said to have included General James Mattis, commander of US Central Command, several senators, and Jeffrey Gordon, a lobbyist who served as a spokesman for the then US defence secretary Robert Gates.

A spokesman Dr Fox said: "Dr Fox took annual leave to attend an awards ceremony in a purely private capacity, no taxpayers' money was spent on this visit."

The spokesman added that during the visit Dr Fox had also met Mr Gates - a meeting at which he was accompanied by two British embassy officials "and no-one else".

Meanwhile, details have emerged of how Mr Werritty allegedly funded his travels.

According to The Times, a corporate intelligence company with an interest in Sri Lanka and a property investor who lobbies for Israel helped channel £147,000 into a not-for-profit company set up by Mr Werritty.

Mr Werritty allegedly used some of the money to join Dr Fox on foreign trips, it was reported.

The money trail also linked Mr Werritty to a venture capitalist keen for stronger ties with Washington, the newspaper said.

David Cameron is under growing pressure to reach a swift decision over Dr Fox's Cabinet.

The Prime Minister has said he will await the outcome of a Whitehall inquiry into the Defence Secretary's links with Mr Werritty, before deciding whether he should keep his job.

But with Cabinet Secretary Sir Gus O'Donnell, who is leading the investigation, not expected to complete his report until next week, the Government faces the prospect of more damaging disclosures over the coming days.

Labour leader Ed Miliband accused Mr Cameron of "delay and indecision" in his handling of the case, saying that he has shown himself to be a "weak Prime Minister."

But Mr Cameron said it would have been weak for him to jump to conclusions before knowing all the facts.

Among the most damaging allegations to emerge are claims that wealthy backers of Dr Fox funded Mr Werritty's work and travel as he joined the Defence Secretary at meetings and conferences around the world over the past 18 months.

Questions have been asked over how Mr Werritty, who was Dr Fox's flatmate and best man at his wedding, could have afforded his globetrotting lifestyle and why he was present at meetings despite having no official position at the Ministry of Defence.

Speaking in Aberdeen, the Prime Minister said: "A strong leader actually recognises you have to take time to get all the information, answer all the questions, and then actually make a decision.

"A weak leader is someone who jumps at it because of some artificial deadline. Let's get the facts established, and then we'll make a decision."

But Mr Miliband said Mr Cameron was showing himself to be "a weak prime minister seemingly unable to make the right decision".

"This uncertainty is not good for the country. We've got a distracted Defence Secretary and a distracted government," he said.

"There is an issue now about delay and indecision at the heart of government. A report should have been commissioned swiftly, and then a decision should have been made."

Meanwhile, Labour MP Anas Sarwar has called on the Electoral Commission to investigate claims that Mr Werritty was effectively a privately funded adviser to the Defence Secretary.

If true, this would be a donation to Dr Fox which would legally have to be declared under the Political Parties, Elections and Referendums Act 2000, said the Glasgow Central MP.

PA