After days of searing headlines about what Mr. Fox has acknowledged as a "blurring" of the line between his official and private lives in his relationship with Adam Werritty, who describes himself as a defense consultant, the government of Prime Minister David Cameron entered the week facing the most serious ministerial crisis in its 17 months in office — and a major distraction, as Mr. Cameron called it, from his focus on the mounting economic crisis in Europe and the challenges it poses for Britain.

In the reckoning of many of Britain's political commentators, there was a strong possibility that the prime minister would ultimately demand Mr. Fox's resignation. That outcome appeared to have been narrowly avoided on Monday, but far from quashed in the light of an inquiry that the prime minister has asked to be completed by the end of next week.

Without offering any broader characterization of his relationship with Mr. Werritty, Mr. Fox, 50, has responded to his critics in Parliament and the news media by accusing them of "a lot of speculation and a lot of innuendo," as well as "constant sniping and undermining," in their questioning of how the relationship affected his defense responsibilities.

Scottish-born like Mr. Fox, the 33-year-old Mr. Werritty has worked for several years as a consultant on defense and health issues, the areas in which Mr. Fox acted as a "shadow minister" for the Conservatives before they won power in 2010.

Mr. Werritty was best man at Mr. Fox's wedding in 2005, and before that Mr. Fox's flatmate in a London apartment where the rent was paid by taxpayers as part of Mr. Fox's parliamentary expenses. He has held no official position in the Defense Ministry or Parliament since Mr. Fox was appointed to the defense post after the election in May 2010. But he has used business cards, as Mr. Fox acknowledged on Monday, that carried the House of Commons logo and identified him as an "adviser" to "the Rt. Hon. Liam Fox, MP."

In his Commons statement on Monday, Mr. Fox sketched a more extensive relationship than the weekend newspapers described. He said he had met with Mr. Werritty 40 times during his period in office — 22 times at the Defense Ministry in London's Whitehall government district, and 18 times on trips abroad. Defense Ministry officials have been quoted in newspapers as saying that top officials at the ministry, including Air Chief Marshal Sir Jock Stirrup, who was Britain's top military officer until last fall, had protested personally to Mr. Fox about the extent of Mr. Werritty's access.

The foreign trips shared by the two included ski trips and other holidays, some of which Mr. Fox took with his wife. But they also included a dinner at which the two men met with senior officers of the United States Central Command, in Tampa, Fla., and with a British defense contractor in Dubai, United Arab Emirates, this year, with no other Defense Ministry officials present, at which the contractor pitched the potential of a cellphone encryption software. Mr. Fox said on Monday that the latter meeting, by creating the appearance of possible impropriety, had been a mistake.

The immediate threat of dismissal receded for Mr. Fox after he offered a personal apology in the House of Commons, following on what he described as an apology to the prime minister, and a similar statement made before reporters on the doorstep of his London home on Sunday.

He won strong backing from fellow Conservatives, particularly from a bloc of right-of-center backbenchers who regard Mr. Fox, one of the most outspokenly pro-American figures in British politics, as a standard-bearer. These backers focused on what they described as his strong performance in the defense post at a time when British forces have been involved in the Afghanistan and Libya conflicts.

But the 75-minute Commons confrontation with Labour Party lawmakers appeared to have provided fresh ammunition to those who have accused Mr. Fox of breaching a code that requires ministers to avoid real or perceived conflicts of interest in their duties.