Until recently, Daniel Hannan's political career appeared to be in rude health. After ten years as a Conservative MEP he had become the darling of the party's libertarian right, acquiring a large following among grass-roots Tories. His speech in the European Parliament denouncing Gordon Brown as a "Brezhnev-era apparatchik" was watched by thousands on YouTube, earning him a prominent slot at the Conservatives' spring conference. His passionate Atlanticism and his stylish turn of phrase had made him a staple of America's conservative talk shows.
But after using a succession of US television appearances to attack Britain's National Health Service, Hannan stands accused of undermining David Cameron's modernising mission and of handing Labour cheap ammunition for a spring election campaign. Hannan has made his views on health care clear for some time - in his most recent book, The Plan: Twelve Months to Renew Britain, published last year, he advocates the introduction of a Singapore-style system of personal accounts - but it took the increasingly fractious debate over President Obama's health-care reforms to bring them to public prominence.
His interview with Fox News's Sean Hannity, in which he appealed to Americans to reject a system "which puts the power of life and death in the hands of a state bureaucracy", appeared to make a mockery of Cameron's claim that the Tories are now "the party of the NHS". Thanks to YouTube - the same medium through which Hannan so impressed the Conservative high command - his comments were replayed effortlessly across the web.
It was the perception that Hannan had gleefully participated in the Republican assaults on Britain's "socialist" health-care system that fuelled the extraordinary media response. Adam Boulton, Sky News's ostensibly non-partisan political editor, was moved to write that Hannan was "an arrogant right-winger in love with the sound of his own voice".
Cameron's decision to intervene so visibly and to portray Hannan as a maverick with "some quite eccentric views" was a tacit acknowledgment that much of the electorate remains sceptical of the Conservatives' commitment to the NHS. But just how did a backbench MEP's views on health policy acquire such importance? And why does this unusually ideological and articulate politician seem to attract, and repel, so many people?
Hannan was born 37 years ago in Lima to a British Peruvian family. He was educated at Marlborough College and later at Oxford University, where he was viewed by his contemporaries as a "Conservative star". During his time at university, he became chairman of the Conservative Association, enjoying a significantly higher profile than his fellow student George Osborne. Harry Mount, an Oxford contemporary who later joined him as a leader writer at the Daily Telegraph, remembers Hannan as an "exceptionally intelligent" figure with a "tremendous" grasp of Shakespeare and a rumbustious sense of humour.
It was at university that Hannan's fervent Euroscepticism began to mature and he channelled his political energies into the Campaign for an Independent Britain. One of his more memorable gestures involved sabotaging the unveiling of a bust of Ted Heath by hiding it shortly before the man who took Britain into Europe appeared.
Hannan's Euroscepticism, like his economic liberalism, strongly reflects the anti-statist turn in Conservative thought in the mid-1970s. This historic shift, profoundly influenced by Friedrich Hayek's The Road to Serfdom, which portrayed economic interventionism as implicitly totalitarian, marked a decisive break with the post-war Keynesian consensus. It is not a romantic or chauvinistic British nationalism that motivates Hannan's support for withdrawal from the EU, but a belief that the union imperils individual liberty.
The first major political controversy of his life came shortly after his election as a Conservative MEP for south-east England in 1999, during William Hague's troubled tenure as Tory leader. Hannan was accused of misusing his public office to raise £100,000 for the Danish No campaign against the single currency and of unreasonably interfering in the internal affairs of a foreign country. He subsequently proved that the fundraising campaign had been run entirely from his Westminster flat and avoided a major investigation by the European Parliament. But his relations with the Danish right came under renewed scrutiny the following month, when he addressed the annual conference of the ultra-nationalist Danish People's Party, whose policies included the chemical castration of sex offenders and compulsory repatriation of asylum-seekers.
Throughout this period, Hannan was consciously protected by Hague, who employed him as a speechwriter, and some figures in the party continue to resent the privileged access he has enjoyed under successive Tory leaders. Hannan is now said to believe that Hague is insufficiently Eurosceptic and that his literary success has lent him an Establishment respectability that he is reluctant to jeopardise. By contrast, he continues to view Cameron with optimism and is confident that the cause of Euroscepticism will flourish under his leadership.
Cameron's pledge to withdraw the Conservatives from the mainstream European People's Party (EPP) and form an alternative Eurosceptic bloc persuaded Hannan to support him in the 2005 leadership election over his right-wing rivals David Davis and Liam Fox. The new alliance finally came into being last month, but Hannan had already been expelled from the EPP a year earlier, after he compared the new powers granted to the German president of the European Parliament to those awarded to Hitler in 1933. Hannan's filibuster tactics, including his persistent use of points of order to forestall votes, proved intolerable to the European authorities. He had consistently sought to embarrass the EU Establishment by ending every speech he made with the Latin flourish "Pactio Olisipio censenda est" ("The Lisbon Treaty must be put to the vote").
After MEPs endorsed the new restrictions, Hannan declared: "It is only my regard for you, Mr Chairman, and my personal affection for you that prevents me from likening it to the Ermächtigungsgesetz of 1933, the Enabling Act with which Hitler won unlimited power, and which was also voted through by a parliamentary majority." Several of Hannan's European colleagues now believe that his use of what philosophers refer to as the "reductio ad Hitlerum" was a cynical ruse to achieve freedom from the federalist EPP.
Even though Hannan has been elected to serve a third five-year term in the European Parliament, his persistent interest in domestic policy has intensified speculation that he longs for a seat in the Commons. Friends of his insist that he plans to serve another full term as an MEP and point out that he has recently moved permanently to Brussels. Others argue that his cerebral nature leaves him unconcerned by the trappings of power.The Conservative blogger Iain Dale tells me: "What pundits don't seem to realise about Hannan is that he does not crave office. He is an ideas man. He gets off on coming up with radical alternatives. He has given up on getting into Westminster and has no ambition to be a minister. That's a pretty powerful position to be in."
Significant parts of Cameron's first major speech after the recent expenses scandal, arguing for a "radical redistribution of power" as the solution to the crisis, appeared to be directly lifted from The Plan, the book Hannan co-authored with the Tory MP Douglas Carswell. Flagship proposals made by Cameron, including reducing whips' powers by introducing elections for select committee chairs and members, and a promise to devolve power to the lowest possible level, were pioneered by Hannan and Carswell.
It is such success that gives the lie to claims by some right-wingers that Hannan is merely the Conservative equivalent of Tony Benn or Dennis Skinner, an eloquent but ultimately impotent maverick. Sunder Katwala, the general secretary of the Fabian Society, believes that the influence of Hannan on domestic policy has been greatly underestimated. He describes him as "the most influential backbench voice in the Conservative Party, despite not being at Westminster" and points out that, with the notable exception of Boris Johnson, Hannan is now the most influential Conservative "who does not owe his position or platform to David Cameron".
It remains too early to judge the effect that the events of the past fortnight have had on Hannan's stock in the party, but for now it is clear that Cameron has refused to abandon his key insight that anything less than unambiguous support for the NHS remains politically and electorally toxic. As Hannan ruefully concedes, the NHS - with 1.4 million workers, the largest employer in Europe and, after the Chinese army and the Indian state railways, the largest in the world - is a constituency no aspirant prime minister can afford to alienate.
Yet should Hannan wish, there is great scope for him to emerge as a lightning rod for right-wing discontent under a future Conservative government. Cameron has already indicated that his party will have to tolerate Labour's new 50p rate of income tax, a policy loathed by many Tory activists. A future Conservative government is also likely to be forced to respond to a nuclear-armed Iran, a policy issue that threatens to expose the growing disparity between the Tory party's neoconservative and realist wings.
Like John Redwood during the mid-1990s - a man Hannan hails as an "Old Testament prophet" - he could become the standard-bearer of the Thatcherite right, those who continue to believe in Conservatism as a transformative project. Hannan's brand of Conservatism, advocating a profound rupture with New Labour, exhilarates those activists privately disquieted by Cameron's more evolutionary approach.
As Katwala argues, a Conservative government "would face stronger internal pressure from the right", and it is Hannan's immense rhetorical appeal that threatens to unravel Cameron's Faustian pact with the Conservative right. It would be a strange twist if this most Eurosceptic of politicians came to wield unprecedented influence from Brussels.
To read George Eaton's media blog visit: http://www.newstatesman.com/blogs/fourth-estate