Some Tory MPs are also looking at Mr Johnson as a potential party leader.

Mr Johnson’s public profile has been enhanced by the London Olympics, and on Monday he upstaged Mr Cameron with a crowd-pleasing speech at a parade of Olympic athletes.

Mr Johnson has also openly criticised Mr Cameron recently over a potential U-turn on Heathrow airport expansion.

He has, however, flatly denied accusations of manoeuvring to win the leadership.

A “radical” new Conservative group was forced to deny it was not trying to undermine Mr Cameron or promote Mr Johnson’s leadership prospects, one of its founders has said.

Conservative Voice was founded yesterday with the backing of senior Tory Right-wingers including David Davis and Dr Liam Fox.

The creation of the group, which wants more focus on issues such as tax cuts, Europe and social mobility, coincides with whispering among Conservative backbenchers about the Prime Minister’s leadership.

Both Mr Davis and Dr Fox are also previous Conservative leadership candidates, defeated by Mr Cameron in 2005.

But Don Porter, the founder of Conservative Voice, insisted that the group was not a threat to Mr Cameron’s authority or a vehicle for leadership challengers.

Mr Johnson, a Daily Telegraph columnist, would need to become an MP again before he becomes leader.

Some Tory MPs are also looking at Mr Johnson as a potential party leader.

Mr Johnson’s public profile has been enhanced by the London Olympics, and on Monday he upstaged Mr Cameron with a crowd-pleasing speech at a parade of Olympic athletes.

Mr Johnson has also openly criticised Mr Cameron recently over a potential U-turn on Heathrow airport expansion.

He has, however, flatly denied accusations of manoeuvring to win the leadership.

A “radical” new Conservative group was forced to deny it was not trying to undermine Mr Cameron or promote Mr Johnson’s leadership prospects, one of its founders has said.

Conservative Voice was founded yesterday with the backing of senior Tory Right-wingers including David Davis and Dr Liam Fox.

The creation of the group, which wants more focus on issues such as tax cuts, Europe and social mobility, coincides with whispering among Conservative backbenchers about the Prime Minister’s leadership.

Both Mr Davis and Dr Fox are also previous Conservative leadership candidates, defeated by Mr Cameron in 2005.

But Don Porter, the founder of Conservative Voice, insisted that the group was not a threat to Mr Cameron’s authority or a vehicle for leadership challengers.

Mr Johnson, a Daily Telegraph columnist, would need to become an MP again before he becomes leader.

“A shot?” I said.

“Yes,” said the fastest man on three wheels, giving me a wink. “I had a boost.” I wasn’t sure that I wanted to hear about this, but curiosity prevailed.

I looked around the tent to see if we were being overheard. “What sort of boost?” I had visions of some galvanic serum for reviving half-dead horses or patients in the throes of cardiac arrest: adrenalin, ketamine, a pint of brandy, perhaps. “I had a shot of beetroot juice,” he said, “and that made all the difference.” As I say, I boggled at him. I wasn’t sure that I had heard correctly, but he assured me that he was serious. “Look it up,” said the Weir Wolf. “Beetroot. It’s much better than caffeine.”

Well, ladies and gentlemen, there you have it. There have been many wonderful things about this summer. Think about the messages we have been sending round the world. Think about it from an investor’s point of view. The Queen’s Diamond Jubilee showed a nation that was profoundly politically stable, with a huge and unexpected reservoir of support for the constitutional settlement. The Olympics showed that we can carry out the most difficult logistical operation demanded of any country in peacetime, and do it with efficiency and style. The Paralympics have shown that Britain remains a beacon of enlightenment.

Oh, yes, I know that from tomorrow evening the cynicism will return. As soon as the victory parade is over the critics will be back, and they will be sniffing about the “legacy”, and wondering whether it was all value for money. There were Olympo-sceptics who were caught out by the euphoria that swept the country. They have been nursing their intellectual defeat, and they will want to mount what criticisms they can. So I say respectfully to any of them tempted to return to their gloomy themes: you were wrong about the Games, and the summer of 2012, and you will be proved wrong about the legacy as well.

Look at what has been done so far: the regeneration of a huge chunk of east London, complete with a vast new shopping centre, thousands of new homes, tens of thousands of new jobs, a superb transport hub at Stratford, and massive improvements to the transport infrastructure of the city. The Games have triggered the biggest explosion of volunteering and general public-spiritedness we have ever seen, with tens of thousands of people now committed to serving their communities. More people are now taking up sport, of all kinds, as a direct result of the Games. All summer long, London has been at the centre of global attention, and billions of households around the world have seen images of a place that looks fantastic and performs well in receiving foreign visitors.

More than anything I can remember, the Games have moved us and brought us together. Total strangers have been talking to each other on the Tube. It is as though the city has been crop-dusted with serotonin.

The Olympics and Paralympics have somehow engendered the very thing all politics is meant to aim for – general happiness and a sense of well-being. We have been united in our admiration for superhuman performances by athletes – British athletes, who have won against the best in the world, and who have been powered by no stimulant more sinister than beetroot juice. The Games have changed not only much of London; they have changed the world’s attitude to Britain, and our own view of this country and what it can do.

Of course, there is a huge job now to secure the legacy – but it is already just about the best £9.3 billion that a government has ever spent.

Other big movers include Ken Clarke, the “big beast” who has left the Cabinet and accepted a more junior role as a Minister Without Portfolio. He will advise the Coalition on economic policy.

Iain Duncan Smith openly defied Mr Cameron by turning down his offer to move from Work and Pensions to Justice, saying that he wanted to stay in his post in order to oversee the implementation of a new form of benefit, the Universal Credit.

In a sign that the Prime Minister heeded calls for more representatives from the Right of the Conservative Party, there were promotions for Theresa Villiers, who joined the Cabinet as Northern Ireland Secretary, Owen Paterson, who became Environment Secretary, and Andrew Mitchell, a popular choice with Tory backbenchers as Chief Whip.

But there was anger at Mr Cameron’s failure to carry out his pledge to bring more women into high office. Caroline Spelman, Cheryl Gillan and Baroness Warsi left their jobs as Environment Secretary, Welsh Secretary and Party Chairman respectfully.

Maria Miller’s appointment as Culture Secretary was not enough to restore the balance of women in the Cabinet. After hours of wrangling, Baroness Warsi reluctantly accepted a new job as a Senior Minister at the Foreign Office.

Grant Shapps was promoted from Housing Minister to become the new Tory Party Chairman.

And David Laws, the Liberal Democrat who resigned over his expenses after just 16 days in office two years ago, returned to the Government as Minister at the Department of Education. He will also have a role advising the Coalition on policy across Government.

There were no changes at the most senior level of the Government, with Nick Clegg, the Deputy Prime Minister, George Osborne, the Chancellor, Theresa May, the Home Secretary, William Hague, the Foreign Secretary, and Vince Cable, the Business Secretary, all staying in their posts.

There were no good guys in that psychotic conflict. At different times and in different places there were members of all religious and ethnic groups – including the Muslims – who exhibited varying degrees of awfulness. And yet the nightmare had a beginning, and at the root of it all was the post-Communist desire of Slovenia and Croatia for greater independence, and the virulent and manipulative reaction of the Serb leader, Slobodan Milosevic.

It was certainly about the revival of “ancient ethnic hatreds”, in the sense that there was plenty of latent poison to be potentiated by maniacs like Milosevic. But it was also about nationalism – the furious desire of one group of people not to be subject to another. It was about the rights of national minorities, whether in Bosnia, Serbia, Croatia or in Yugoslavia as a whole, and their struggle against the majoritarian tyranny —whether from Belgrade, Zagreb, or even Sarajevo. Peace was only brought about by the complete dissolution of Yugoslavia, the loss of tens of thousands of lives, and the biggest forced movements of peoples since the Second World War.

Croatia effectively won its war in 1995, when Ante Gotovina led the operation that booted the Serbs out of the Krajina. But by then the Croats already boasted all the attributes of full statehood – the logical inevitability of the German-led recognition of January 15, 1992. They had an independent parliament, an independent legal system, and they had what every country needs if it wants to be truly the master of its own destiny. In 1994 the Croats scrapped the Yugoslav dinar – symbol not just of Communist oppression but rule from Belgrade – and introduced the kuna.

The kuna is named after the word for a pine marten, whose pelt was used in medieval Croatia as a store of value, and in the last 18 years it has served the country well. The place is obviously prosperous. The streets are clean, the roads are fast and smooth, the supermarkets are stocked with every conceivable delicacy in the kind of air-conditioned hygiene you might expect in Austria. Tourist money is flooding in on Easyjet flights and on the yachts of the super-rich.

The Croats are making their mark on the world of sport, with three gold medals at this summer’s Games – six medals in all – which is not bad for a country of only four and a half million people. Croatia seems to have a wonderful future.

That makes it all the more astonishing that the Croats should apparently be prepared to swap one doomed federal structure for another. As we are seeing in the eurozone today, monetary union is not remotely compatible with fiscal independence. In the case of Greece, Spain and other countries, it means a protracted process of greater or lesser humiliation at the hands of bureaucrats from Brussels. It means the hollowing out of democracy. It means ignoring and overruling the sovereign politicians of minor states.

The euro makes an absolute mockery of independence, self-determination – all the things so many Croats fought and died for. Sure, the tyranny of Brussels is not a violent one, and it is not as poisonous as the tyranny of Belgrade. It is a velvet kind of tyranny, but a tyranny none the less.

Avoid the euro, my Croatian friends. In 10 years’ time I want to go back, order a bottle of superb red Dingac, and pay for it in kuna.

That’s what transfixed my family and hundreds of millions of others. We were watching human beings overcome what we had always assumed was a basic limitation of our species to break a barrier that was physically or psychologically insurmountable. We were watching a triumph of the human spirit — and that, of course, is exactly why so many people are getting ready to enjoy this week’s Paralympic Games.

Not since the Paralympic movement began in 1948 has there been such a rush for tickets. Of the total of 2.4 million, there are only 200,000 still to be sold, and they are being snapped up as fast as Olympic tickets were — as fast as Locog can put them on to the website. We are getting ready for live sites in Trafalgar Square and Potters Fields, and Channel 4 is going to be running 150 hours of prime-time television. The International Paralympic Committee say they have never seen such interest and enthusiasm from any public. Without counting our chickens, we are confident that London will complete the success of the summer of 2012, and put on a wonderful Paralympic Games.

There will be prodigious displays of sporting excellence (for my money, wheelchair basketball is far better and more murderous than the other type). Indeed, there are some purists who say that we shouldn’t really be talking about the “back stories” of these amazing performers. They argue that we should simply see them as athletes, and blot out the difficulties they overcome. I hope I will be forgiven if I say I can’t see it like that. All athletes have a back story. Every athlete has had a barrier to surmount.

Is it relevant to our appreciation of Laura Trott that she was born with a collapsed lung? Too right it is. There isn’t a sportsman or woman alive who hasn’t at some time or other been called upon to show inner steel, and the Paralympians have had to overcome adversity in a way that is mesmerising, heartbreaking and inspiring. There are men and women who have been told by their doctors that they are beyond hope, who have been left for dead, who have come back from terrible accidents or injuries. These are people who have so comprehensively vanquished disability that they are defined by what they can do rather than what they can’t do. When Oscar Pistorius was a baby, his mother wrote him a letter that she intended for him to read as an adult. “The real loser is never the person who crosses the finishing line last,” she told him. “The real loser is the person who sits on the side, and does not even try to compete.”

Oscar Pistorius, who has no legs below the knee, is now one of the fastest men in the world. These people have The Right Stuff by the bucketload, exploding from every pore. When we watch them, we see the same phenomenon that drew the world round the TV set in 1969. It is the human urge to try, to risk, to dare, to master our fear and dive in; and then to keep doing the same until we succeed.

We admire that spirit in some deep and probably primeval way. It is, after all, the same competitive spark that produced just about every example of social, cultural, material and economic progress in the past 10,000 years. It was the spirit that drove Mo Farah and Jessica Ennis in those amazing and unforgettable Olympics of earlier this month. It was what got Neil Armstrong on to that Gemini programme, into the lunar module and on to the surface of the Moon.

It’s The Right Stuff, and the Paralympians have more of it than just about anyone else in the world.

Calling on his rival to be more “ambitious” on the economy, the Mayor said in an interview with the London Evening Standard: “The Government needs to stop pussyfooting around.

“The way to get business really motoring in the UK is to cut taxes, cut regulation, create the infrastructure and get behind it. That’s what you should do.

“There’s a real opportunity to capitalise on the Olympics. [To] look at London as the motor that can drive growth.

“This is the time to be ambitious about London and what it can do for Britain. One of the ways of doing that would be to commit to further infrastructure — Crossrail 2, more river crossings, a massive house building programme for the city.”

Should Boris Johnson be Prime Minister?

Last month, the Government delayed the publication of a consultation into the future of Britain’s airports, amid reports that Justine Greening, the Transport Secretary, was opposed to the building of a third runway at Heathrow, the option thought to be favoured by Mr Cameron and George Osborne, the Chancellor.

Mr Johnson, who wants to see a new airport built in the Thames to help relieve London’s overstretched terminals, described the delay as “totally mad”.

Claiming that Mr Osborne is “actually very much up for big ideas like this,” and that Miss Greening “gets” the idea for a new four-runway airport, dubbed “Boris Island,”, he said the Prime Minister had yet to be convinced, blaming the “institutional inertia of the Government.”

“Heathrow is fundamentally not the place” for further expansion,” Mr Johnson added. “I think there’s a bit of institutional capture. But it’s a totally blind alley.

“The attempt to try and long-grass it for three years into the other side of the election is just not realistic. Totally mad and it won’t work.”

The Mayor disclosed that Mr Cameron had grabbed him in a bear hug while they posed for photographs during the Games – leading Mr Johnson to grasp the opportunity to hiss in the Prime Minister’s ear: “airport.”

And he called on the Government to take advantage of the Olympics to cement London’s place in the world.

He said: “I think that what the Olympics has done is to confirm in a lot of people’s minds around the world that London is the capital of the planet. What I think the Government should do is make a very powerful statement of ambition for London.”

The poll of 547 Labour supporters by the website LabourList found that 51 per cent agreed with the statement that “Boris would be harder to beat than Cameron,” with 22 per cent disagreeing and a further 22 per cent saying it would make no difference.