Picasso's Deux Personnages (La Lecture)
Picasso's Deux Personnages (La Lecture) is predicted to sell for £13m-£18mSotheby's

Sotheby's is set to mount the most expensive ever art sales in British history over the next fortnight, with more than £400m worth of paintings on offer.

Works by Francis Bacon, David Hockney, Andy Warhol, Lucian Freud, Édouard Manet, Edgar Degas, Gustav Klimt, Pablo Picasso and Paul Gauguin are up for sale.

New ground is set to be broken at the impressionist and modern sale this Wednesday evening together with contemporary sale a week later. The sales include 12 works which are each expected to sell for more than £10m.

Many buyers are expected to be billionaires. In an interview with The Times, Helena Newman, Sotheby's joint global head of impressionist and modern art, said there was, "an enormous global appetite, with collectors looking for the best of the best".

Her colleague Cheyenne Westphal, also joint global head of impressionist and modern art, said that the trend towards purchases by billionaire buyers from China, South America, the Middle East and Russia was accelerating. Of London itself, Westphal added: "We have a truly global audience that lives here."

The top end of the fine art market has seen an extreme scenario of asset inflation since the advent of the financial crisis back in 2008. Factors behind frenetic competition among wealthy buyers include low returns on monetary assets, and the increasing numbers and purchasing power of the super rich on the other.

Perhaps appropriately, the works on offer include a collection of Andy Warhol's dollar paintings. Sotheby's say they could reach £57m. Francis Bacon's Study for a Pope I is predicted to fetch between £25m-£35m, while Kazimir Malevich's Suprematism, 18th Construction, has an estimate of £20m-£30m. The latter has never been auctioned before.

"Bringing this kind of quality into the open is a big driver up of prices," said Westphal of the Malevich. "There is a palpable excitement when something has not been seen in a very long time."