Boris Johnson the real Tory is about to make life much harder for David Cameron So what about Boris? The idea of him as prime minister was first raised in a Spectator editorial meeting almost 10 years ago, to the hearty laughter of everyone on the room - with one exception. The man in question, the magazine's then editor, looked a little put out, almost hurt. But no one is laughing at him now. The bookmakers have Boris as favourite to succeed Cameron; the fact that he has no Commons seat is a mere detail. Lesser men may feel they ought to choose between being mayor and an MP, but as Boris once said, "My position on cake is pro-having it, and pro-eating it." Around the Commons, various names are touted (Crispin Blunt, Patrick Mercer) as men who may step down to allow the return of the king over the water. Boris has spent his life being underestimated. When he became editor of The Spectator, one unkind soul said the appointment was like "entrusting a Ming vase to the hands of an ape." The vase emerged in as good a shape as the London mayoralty has today. His skill lies not so much in management, as in picking and inspiring brilliant people on whom he relies completely. His election campaign has been run with great discipline by the Australian strategist Lynton Crosby, who turned down an offer to work for the Prime Minister. His people can see in Boris a sense of fun and political mission that is not always evident in the Government. Whether this team - or any team - could take him to Downing St is another matter. Cameron teases Boris about his ambition, but the leap from mayor to prime minister is a large one. A private poll conducted recently by YouGov Cambridge showed that the Tories would do four points worse with Boris than Cameron. This may be because he has not pitched himself to voters outside the city, and lacks the PM's profile. Or it may be because voters know him all too well, and shudder at the image of him accidentally resting his rucksack on the nuclear button. And while Tory MPs do have a habit of mulling leadership putsches, many resent the idea of Boris swanning in and grabbing the crown. The real question Boris poses to Cameron is not one of leadership, but direction. The flatlining economy, plunging poll ratings and relentlessly bad headlines have all contributed to a sense that - as the Tory leader said at the last election - we can't go on like this. Events will force the Conservatives to adopt a more radical agenda, and challenge the Lib Dems to trigger an election if they don't like it. In particular, if the eurozone implodes, it will create an unmissable opportunity to renegotiate Britain's membership of the EU. Only in Westminster could this be considered an extreme position: according to the latest research, the British public are more hostile to Europe than even the Greeks. Euroscepticism is now the opinion of mainstream Britain. Intriguingly, Tory MPs who have vented their frustration to George Osborne on this issue have come away with the impression that the Chancellor is on their side: that he regards a bust-up with Brussels as inevitable, and is also getting fed up with the power given to the Lib Dems - not least the way that Cameron and Nick Clegg always arrive late for Cabinet meetings, having obviously been making all the key decisions before they enter the room. Whether the Chancellor's frustration is real or confected, he is hardly likely to admit to it in public. Boris, however, has no such constraints: he has a pulpit, and can be expected to use it to create much mischief. Even if he never progresses past City Hall, he may very well have changed the terms of debate. Until now, Tories had been told that there were two types of Conservatism: the "modernising" type, and the type that failed so abysmally in 2001 and 2005. Now, the modernisation project itself looks dated, self-loathing and electorally unpopular. A new type of "Boris Conservatism" is emerging: vivacious, self-confident and able to capture voters" imagination in the cities as much as the shires. However much mischief he causes for Cameron in the months ahead, he has already done their party an almighty service. Fraser Nelson is Editor of 'The Spectator