Image copyright King's College Image caption Paul Cezanne's Still Life with Apples, c 1878

How did a priceless masterpiece by Cezanne come to find itself in a hedge by a Sussex farm track during World War One, asks Trevor Dann.

It's one of the lesser known but most fascinating tales of World War One. What was the British government doing buying paintings at a Paris auction house while German guns were bombarding the city? And how did a priceless masterpiece by Cezanne come to find itself in a hedge by a Sussex farm track?

Maynard Keynes (he never used the John) is best known as a great economist, who believed strongly in state intervention in the market. He helped found both the World Bank and the International Monetary Fund. But less well-known is that he was a key member of the Bloomsbury Group, an avid art collector and the founder of the Arts Council.

A strange combination of events in 1918 allowed Keynes, then a humble Treasury adviser, to combine his two great passions, money and art.

More on John Maynard Keynes Image copyright Getty Images John Maynard Keynes (1883-1946) was educated at Eton and Cambridge University, where he studied mathematics

He became friends with members of the Bloomsbury Group of intellectuals and artists

Keynes joined the Treasury during World War I, and in the wake of the 1919 Versailles peace treaty, published The Economic Consequences of the Peace , criticising exorbitant war reparations demanded from Germany, claiming they would harm the country's economy and could foster a desire for revenge

, criticising exorbitant war reparations demanded from Germany, claiming they would harm the country's economy and could foster a desire for revenge During inter-war years, Keynes became a prominent arts patron

His best-known work The General Theory of Employment, Interest and Money, published in 1936, made Keynes Britain's most influential economist

published in 1936, made Keynes Britain's most influential economist Keynes led 1944 British delegation to the Bretton Woods conference in the United States, playing an important role in the planning of the World Bank and International Monetary Fund A Point of View: What would Keynes do? Keynes v Hayek: Giants of economics

His Bloomsbury friend, the art critic Roger Fry, told him about a sale of impressionist works from the collection of the artist Edgar Degas, who had recently died. Fry believed that painters like Cezanne, Manet and Gauguin were geniuses whose work was unrecognised by the British. He thought they should be on show at the National Gallery and that the forthcoming wartime auction would allow them to be bought cheaply.

Keynes agreed but added an idea of his own. The British government had borrowed considerable amounts of money from the US to help them fight the war. They had lent much of it on to the French, who would never be in a position to pay it back. So Keynes argued that he could purchase a few paintings, which would grow in value, for effectively nothing. It was positively, well, Keynesian.

And so, as the war continued to rage in the trenches of Flanders and northern France, Keynes and the director of The National Gallery, Sir Charles Holmes, caught a boat train to Boulogne and travelled by train to Paris with £20,000 in French banknotes. Aware that the French would be reluctant to sell to a British bidder, Holmes shaved off his moustache and adopted a faux French accent. As the auction began, Paris was rocked by the sound of shells from a German super-gun, firing from a railway line 80 miles away. Some bidders fled, prices tumbled, and Holmes and Keynes were able to secure some real bargains.

In the National Gallery today, Holmes's successor, Dr Nicholas Penny, proudly shows off the works which kicked off the gallery's collection of modern art. Manet's massive Execution of Maximilian, cut up in the 19th Century and now partially reassembled, is a most impressive painting and one of the gallery's most popular exhibits. But no less remarkable are A Portrait Of Baron Schwitter, with his Michael Jackson-style white glove, by Delacroix, Corot's The Roman Campana, a tiny painting of Oedipus and the Sphinx by Ingres, and Flower Piece by Gauguin. Penny says that the Impressionist and Post-Impressionist rooms at the National Gallery are the most popular in the entire building. Without Keynes's efforts, none of these masterpieces would be on show in the UK.

Image copyright Alamy Image caption Manet's The Execution of Maximilian

But Sir Charles Holmes's enthusiasm for modern art did not stretch as far as Cezanne. He refused to buy the beautiful Pommes, an exquisite portrait of seven apples in a fruit bowl. Keynes was so horrified by this decision that he bid for it himself and secured it for £500.

When he arrived here he said 'if you'd like to go down to the road, there's a Cezanne just behind the gate' Duncan Grant, 1969

At the end of the auction, the intrepid art collectors were joined by the diplomat Austen Chamberlain, who offered Keynes a lift from Folkestone to the village of Charleston in Sussex, where Virginia Woolf's sister Vanessa Bell shared a farmhouse with Clive Bell and Keynes's lover Duncan Grant.

The track from the main road was too muddy for Chamberlain's "government motor" and Keynes couldn't carry all his luggage. So he left the Cezanne under a hedge and walked half a mile to the Bloomsbury Group's house. Speaking to the BBC in 1969, Duncan Grant took up the story: "When he arrived here he said 'if you'd like to go down to the road, there's a Cezanne just behind the gate'." Vanessa Bell wrote that "it was all very exciting" but chastised Keynes for not spending the entire £20,000 and returning home with £5,000 unspent.

Keynes kept the Cezanne over his bed. When he died in 1946 it was bequeathed to King's College, Cambridge, where Keynes kept rooms all his life. Today it hangs in Cambridge's Fitzwilliam Museum for everyone to enjoy.

Image caption The Sussex hedge which briefly housed the still-life by Cezanne

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