“She would have approved.” So said one of Liam Fox’s admirers, without feeling any need to put a name to “she”. Fox is a hero to the many Conservatives who not only revere the memory of Margaret Thatcher, but also believe that unabashed Thatcherism is what is required now.

They praise Fox for sounding “principled” rather than “wishy-washy”. They laud him for being “a proper Eurosceptic” who wants strict immigration controls. They love his loyalty to old friends, and deep commitment to the Anglo-American relationship. They admire him as a communicator, relish his joie de vivre, and when asked if they would like him to be given a senior post in the next reshuffle, insist that they most certainly would.

It is only when one asks what that post should be that some of the admirers begin to falter. Fox resigned as Defence Secretary in October 2011. If he comes back, the assumption is that he would have to be offered a similarly senior post, which he would occupy at someone else’s expense. And few people can see, at first glance, what that post might be.

But the strength of pro-Fox feeling is still rather striking, and serves as a reminder of the underlying precariousness of the Prime Minister’s position, and confirmation of the skill and care he has to devote to managing his own party.

For David Cameron’s leadership has not just left a considerable part of his party untouched. It has inspired a craving for a much more assertive conservatism, in which there would be no room for doing deals with the Liberal Democrats.

Fox helped to demonstrate during the last Tory leadership contest, held at the end of 2005, the large volume of support which exists for this kind of unrepentant conservatism. Some of the MPs who backed him then have tended to remain loyal to him since. In the second and final round of voting among Tory MPs, he obtained 51 votes, compared to 57 votes for David Davis and 90 for David Cameron. Davis and Cameron therefore went through as the two candidates to be considered by the wider Conservative membership: a contest which Cameron won by a convincing margin.

But it will be noted that in the final ballot of Tory MPs, Fox and Davis, both of whom were unabashed Thatcherites, between them obtained more votes than Cameron did. And many observers reckon that although Cameron would have been able to beat Fox in the final run-off, he would have found this battle considerably harder than it was to beat Davis.

For at the 2005 Conservative Party Conference, addressed by all the aspirants to the leadership including Ken Clarke and Malcolm Rifkind, it was generally agreed that Fox gave a more impressive performance than Davis. I happened to talk, while writing this profile, to a floating voter who watched all the speeches on television, including Cameron’s acclaimed performance without notes. She said:

“I actually thought Fox was the best. He was the man who was most in touch: he’d been a doctor, he’d been out there. If I’d had a vote I’d have voted for him even though I didn’t agree with his right-wing policies.”

Fox told the conference:

“We need to re-establish pride in what it means to be British. Pride in our national identity. We have spent so long focusing on diversity that we have forgotten to focus on what we have in common.”

He also took aim at Davis, who had been trading on his humble origins as the son of a single mother on a council estate. Fox declared:

“My father was a teacher, my mother was a housewife, my grandfathers were both miners, I went to the local comprehensive, I trained in medicine and worked in the NHS as a hospital doctor and a GP. None of these, none of these are reasons for me to become leader of the Conservative party.”

The Cameroons were perturbed by Fox’s success. When Fox, as an expression of his passionate Euroscepticism, said he would tell Tory MEPs to leave the European People’s Party, Cameron felt obliged to match this pledge. It was also Fox who began talking about the “broken society”, an expression afterwards picked up by Cameron.

Some of Fox’s supporters believe that in the final ballot of Tory MPs, the Cameron camp lent Davis a few votes in order to ensure that Fox came third. After getting off to a slow start, Fox had imposed his personality on the contest with a surprising degree of success.

In an interview the previous year in the Daily Telegraph, carried out by Alice Thomson, Fox (at that time co-chairman of the Tory party) had expressed with marvellous clarity the conviction of the Thatcherites that their time would come. When it was put to him that the Conservatives under William Hague had lost the 2001 general election by concentrating too heavily on Europe and immigration, Fox replied:

“William had many of the right issues – it was just the wrong election. We were highlighting trends that voters hadn’t yet come to comprehend.”

The voters, he suggested, would learn to share the same priorities as Tory MPs. Thomson also described the somewhat louche figure which Fox cut at Westminster:

“The last time I went to interview Liam Fox, he had drunk so much the night before that he had forgotten our appointment. That was five years ago, the day after enthusiastic birthday celebrations involving whisky and Sambucas, when he was the wild child of the Conservative Party. Back then, he frequented nightclubs, went skydiving with Tesco check-out women and was seen out with the pop star Natalie Imbruglia. Dr Fox – who was voted sexiest MP – seemed the perfect antidote to all those lifeless corpses in his party…He was the raucous usher at William Hague’s wedding and had a ‘Stuff the EU’ sticker on his bumper plate. His friends ranged from Mother Teresa, with whom he kept up a regular correspondence, to Cindy from EastEnders.”

Fox, who is 52, lacks the inhibitions found in some Conservatives born in easier circumstances. He has also achieved by hard work and ability success in two different professions. His friends say he has “the most amazing stamina”. He was born in East Kilbride, near Glasgow, went to a Roman Catholic school, St Bride’s, and read medicine at Glasgow University, where in the early years of Thatcher’s leadership he was President of the Glasgow University Conservative Association: not a fashionable allegiance at that time.

He practised as a GP in Buckinghamshire, and also as a Civilian Army Medical Officer, and in the general election of 1987 fought Roxburgh and Berwickshire, where he lost to the Liberal candidate by 4,000 votes.

In 1992, he was elected as the MP for Woodspring, since renamed North Somerset, a seat which he has held ever since.

Fox was soon marked out for preferment. In 1993 he became parliamentary private secretary to Michael Howard, in 1994 he was made a whip and in 1996 he became a Foreign Office minister. He is deeply interested in foreign affairs and possesses a remarkable number of high-level contacts, especially in the United States.

During the Tories’ years in opposition, he held various Shadow Cabinet posts, including the health brief, where he declared that it was “time to end the serfdom of the NHS monopoly”. Many Tory MPs agreed wholeheartedly with this line, but voters tended to be unsettled by it, and to conclude that the NHS would not be safe in Tory hands.

In December 2005, after winning the leadership battle, Cameron made Fox Shadow Defence Secretary. So by the time the Tories came into government in 2010, Fox was well prepared. He nevertheless became involved in a bitter row about defence cuts, during which a letter of protest which he wrote to Cameron was somehow leaked.

In 2011, Fox was hit by a series of revelations about Adam Werritty, a friend of his who had acted as the best man at his wedding and had accompanied him on a large number of foreign trips made as Defence Secretary, as well as coming in to the Ministry of Defence on numerous occasions.

There was nothing illegal about this: Fox has recently won a libel action against a businessman who had suggested that there was. But even some of Fox’s fans thought his close relationship with Werritty looked extremely odd. One of them pointed out that Thatcher and Churchill had also had some weird hangers-on. But Fox’s position became untenable and he resigned.

The Cameroons were not entirely sorry to see him go. Matthew d’Ancona says of him, in In It Together – The Inside Story of the Coalition Government: “His portentous manner, syncopated grin and eye-widening tic encouraged the belief he was either mad or a genius.”

Yet Fox has avoided stirring up trouble and is still on very friendly terms with a number of members of the Cabinet. He has written a well-received book, Rising Tides, about the various threats facing the world, which he summarised in the Daily Mail under the headline “Ten global nightmares that should keep us all up at night”. He makes deeply felt arguments about immigration. In a recent piece in the Daily Mail he contended: “There is a world of difference between a European banker coming to work here and an unskilled agricultural worker who ends up a burden on the welfare state.” The Daily Mail also reported at the start of this year, just after Fox’s annual New Year’s party at the Carlton Club, a rumour that he might become the next Secretary-General of Nato.

But just as a new generation of players is emerging at Wimbledon, so Fox must worry that he is being overtaken by a new generation of MPs at Westminster. Many people are bound to be disappointed in the forthcoming reshuffle, for there are not enough jobs to go round. It will perhaps be intimated to them that they will get the promotions they deserve if and when the Tories win the 2015 general election outright and can dispense with the services of the Liberal Democrats. A minister denied that this reshuffle is Fox’s last chance of coming back, and implied that this might equally well happen in 2015.

But what if these hints are just designed to quell dissent by keeping supplicants hanging on for favours that are never actually granted? And what if Fox is seen as too much his own man? While competing for the Tory leadership, he declared, after calling for the abortion time limit to be reduced to 12 to 14 weeks: “I’m not going to pretend that my views are other than they are for the sake of political convenience.” The candour that lends him authenticity could also sink him.