His battered Renault van was my first clue that Michel-Jack Chasseuil was not going to be your average wine collector. In possession of what has been dubbed the world’s largest private collection, Chasseuil’s 40,000 bottles, 3,000 magnums and 3,000 spirits might be worth anything from €50 million to €500 million, depending on the day and the buyer.

Michel-Jack Chasseuil shows off his collection of Petrus. Image credit: Getty / AFP

But he tells me that he stopped buying Bordeaux en primeur in 2010, when the prices became unsupportable, that he borrowed around one million euros from the bank to make most of his purchases in the 10 years leading up to that, and that he hasn’t opened a bottle of fine wine from his ‘inner’ cellar for almost 25 years.

We arranged to meet outside the church in the tiny hamlet of La Chapelle Baton in the Poitou-Charente where he grew up and where his father worked as the village postman. His childhood house was right there next to the church.

‘My grandfather bought and sold cattle, and often picked up barrels of wine along the way. Each January he gave 100 bottles to each of his 11 children, including my mother’. And by the time Chasseuil was a teenager, he had begun keeping back a few of these – ‘the ones with corks, which meant they were quality’ – to begin his own collection, soon using every spare penny (‘I’ve never had a car that isn’t falling apart’) on searching out other bottles, at first largely through auctions in Paris. And it quickly became obsessive. He spent 10,000 francs on a case of Quinta do Noval Nacional 1963 when he earned 5,000 francs per year, and by 1970, before his 30th birthday, had already amassed 1,000 bottles.

Chasseuil is now living in his grandmother’s house, a few winding country roads away from his first home. It joins the Renault in being resolutely low key – exposed stone walls, low ceilings, furniture that looks distinctly more old and unloved than antique. It’s not until you step out into the breathtakingly beautiful garden – all created by Chasseuil himself, from carving out the lake to indulging in a spot of wine-bottle-shaped topiary – that you start to get a taste of what drives a man who now counts among his treasures every vintage of Romanée Conti since 1904, every Petrus since 1914, every Yquem since 1900 and a vast 600-bottle collection of the legendary Massandra wine from Crimea.

Not that you can accuse him of downplaying the importance of his collection, which is held in three separate rooms in an underground bunker accessed via a series of steel doors and stiflingly narrow tunnels. Over the course of our four-hour meeting, he referred to it as the Louvre of Wine – a reference to the Parisian museum – the UNESCO of Wine and the Pantheon of Wine.

‘This is the best 240 producers from 39 countries across the world, in all the best vintages, many that are so rare that they no longer exist outside of these walls.’

Not surprisingly, he receives requests to visit his cellars daily – from sommeliers, journalists, heads of state, wine producers and fellow collectors.

But last year he also attracted the attention of ‘five men with Kalashnikovs’ who broke two fingers and threatened far worse in an attempt to get access to his lucrative bottles. They failed, but despite his breezy assurances that he’s beaten them, it’s hard not to imagine that this has added a sense of urgency to the plan of moving his wine collection out of La Chapelle Baton and into a permanent museum where it can be donated to the nation. He first created the Chasseuil Foundation in 2012, and appointed as executors his son Jeremy Chasseuil of Chateau Feytit-Clinet in Pomerol together with Marcel Guigal.

Reactions have been mixed. According to Chasseuil, he has been refusing offers to house the museum in, among other places, the Imperial City in Beijing and the Cité des Civilisations du Vin in Bordeaux, and is instead determined to bring it to Paris. He tells me that the French government is ‘considering’ donating the basement of the Hôtel de la Marine in Paris as the location for his wine museum, with a gallery to the glory of French gastronomy planned on the ground floor by Alain Ducasse and architect Jean-Michel Wilmotte.

While it is true that UNESCO in 2010 recognised wine as part of the country’s gastronomic prowess when including it on the ‘world intangible heritage’ list, all of the research that I did found that there are already objections piling up. Will a museum to wine pass in a country where the Evin Law holds such sway? And will a government that already sold part of its own Elysée cellar – Chasseuil was a prominent objector – really be prepared to underwrite a wine museum in a national monument?

It’s all quite disorientating really. Chasseuil is 74 but has the energy of a much younger man. He is great company, clearly extremely bright. As we walk around the cellar, the names on the cases become ever more dizzying, and it’s hard not to agree that bottles such as an 1865 Sicilian Vin de Zucco from vineyards established by the Duc d’Aumale, or an 1805 bottle of Cognac owned by Napoleon Bonaparte – with an accompanying letter signed by Napoleon – have some value in the public space. Chasseuil claims that he doesn’t want these bottles to end up in the hands of rich collectors but to be tasted by wine students and scientists – alongside tastings for those who will pay heftily to underwrite the Foundation’s more noble aims.

Yet as with all true obsessives, he displays a religious zeal that can be difficult to keep up with. He tells me that since his divorce in 1975, and certainly since leaving his job as an aeronautical engineer for Dassault in 1990, he has consecrated himself full-time (‘8am to 8pm, seven days a week’) to building up this collection. These days that means raising money for his Foundation, and through it the wine museum, with a series of wine dinners and other projects. The idea is seductive but the details remain hazy. He says things like ‘if every sommelier in the world gave €1 then we would have enough’.

But there is no doubting his sincerity. ‘Climate change will make fine wine even more like works of art. Eventually it will be like 1789 when these bottles are only available to the aristocracy, which is why I want to create a conservatory to honour them’.

As I prepare to leave, a group of wine lovers arrive for a paid tasting of a few of his more recent wines. The Russian ambassador is due the following morning to discuss the wines held in Magarach Institute in Russia. You get the feeling that he won’t leave without having promised a few of these increasingly rare bottles to the Chasseuil Foundation, convinced by the insane genius of Michel-Jack Chasseuil.

Written by Jane Anson