Something important happened this week in France that had nothing to do with the Bayeux tapestry, frontier controls at Calais or the future of Anglo-French cooperation on European security and defence.

On Wednesday, in a dramatic personal intervention, President Macron put his pen through plans to construct a massive new airport between Nantes and Rennes intended to take pressure off Paris’s Charles De Gaulle and provide an international gateway into western France. In doing so, he reversed a previous pledge to respect the result of a departmental referendum in which 55 per cent of voters, with an eye to jobs and inward investment, had declared themselves in favour of the project.

It was as if Theresa May had announced that she had cancelled HS2 and abandoned plans to build a third runway at Heathrow.

Plans for the airport, known as Notre-Dame-des-Landes, had been a thorn in the side of successive French governments. The costs were huge and rising, and the utility unproven to the satisfaction of thousands of protesters and millions of voters. Presidents Sarkozy and Hollande pretended to ignore the depth of the opposition, observing, as if it had nothing to do with them, that the decision had been taken and that those opposed should find better ways to occupy their time.

But the campaign to stop the airport continued unabated. If anything, it gained in support, not only in the region around Nantes and Rennes, but as a cause célèbre across France. The risk was that nothing would get done one way or the other, leading to the kind of stasis that exposes governments to public ridicule.

It was at this point that Macron acted. Like De Gaulle and Mitterrand in their pomp, he gave commands, and all argument ceased. As a populist himself, the President could see what was happening. Vitally, he realised that he, and he alone, could made the difference. An issue that had festered for years was resolved with a simple instruction – annulé – relayed and approved by his prime minister and representative on Earth, Édouard Philippe.

The protesters, including a growing army of squatters, were shocked and overjoyed. Known as Zadistes (from zone à défendre), they believe they have won a great victory. Macron, at the same time, has burnished his somewhat faded liberal credentials.

There will, of course, be a cost. Nothing comes for free in statecraft. France will now have to look again at its strategy of routing nearly all international arrivals, especially those from the Americas, via Charles de Gaulle. Vinci, the airport’s lead contractor, will demand compensation. But Macron, still less than a year into his presidency, has shown what a head of state can do under the monarchial rules of the Fifth Republic. He can make and unmake grand decisions, including his own. Like a general – like, he would say, Napoleon – he has the power to do what mere parliamentarians can only dream of.

It is not, of course, all about the power of office. The presidency is what you make of it. Nicolas Sarkozy wanted, deperately, to be a memorable leader of his nation. Instead, he ended up as the King of Bling. François Hollande would have given anything – other, perhaps, than his right to visit his mistress on the back of a chauffeur-driven scooter – for a single drop of the charisma that seems to envelope Macron. But neither man had the confidence, one might even say the aura of invincibility, that currently surrounds the one-time investment banker from Amiens. They would have looked at the sheer enormity of the airport crisis and made themselves ill, fearful of the possible outcomes. Not Macron. The Jupiterean President weighed up the risks, studied the reports and decided that the best thing to do was to cut the gordian knot.

Theresa May, who spent much of Thursday closeted with Macron in Sandhurst, must surely have envied him his freedom to act. Her visitor, in turn, will have asked himself what the point is in being head of government if you are not obviously in a position to take the big decisions.

Margaret Thatcher, in 1983, might have had the balls to act as Macron did. Tony Blair, at the height of his popularity, pre-the invasion of Iraq, could have attempted a similar stroke. Both, however, would first have had to consider the parliamentary arithmetic. The findings of committees and commissions of inquiry would have been scrutinised for let-out cluases. The chairman of the 1922 Committee or the general secretary of the TUC would have been called in. And Downing Street would first have briefed friends in the media, knowing that executive overreach could result in a Commons revolt.

As David Cameron discovered over his proposed military intervention in Syria in 2013, a British prime minister cannot even launch airstrikes these days without the backing of MPs.

Few such restrictions affect the French head of state. Macron sails blithely on, charming the British, impressing the Germans, convincing the Trump Administration in Washington that France, against all the evidence, remains a major power in the world. He knows that this is his moment, his period of maximum opportunity, and he is determined not to waste it. How long he can continue like this is unclear. Eventually there will be a reckoning. But for now he is king in his castle, using the powers given him by De Gaulle’s constitution to give a firm lead to his country, taking it out of the doldrums into what passes for the sunlit uplands.

Can one man, or one woman, make a difference? Emmanuel Macron is showing that to strike when the iron is hot, you must first wield the hammer.