Why a portrait of Francis Bacon terrifies us all

Tonight, Lucian Freud's portrait of his friend Francis Bacon is to be auctioned. The art world hopes it will net £7m, but there are signs the market is stalling. So will the Christie's sale indicate that the global financial crisis is about to get worse?

The face seems to be peering through a tear in the canvas, lips pursed and eyes downcast. To the art world, and the rest of us, this could be the face of doom.

The portrait of Francis Bacon by fellow artist Lucian Freud is the centrepiece of an important sale today. Christie's auction house hopes it will fetch £7m. If it doesn't – as now seems likely – dealers in the previously lavish market for contemporary art will know that they face deep financial trouble. It will also indicate that the global financial crisis is affecting even the super-rich.

The Frieze Art Fair last week attracted stars such as Gwyneth Paltrow but sale prices were much lower than expected. The signs are that buyers are holding back until they know what happens to the Freud portrait: it's seen as the canary in the coalmine that could tell everyone the market is about to blow.

"There is a lot of apprehension in the trade," said Charles Dupplin of the art insurance company Hiscox. Staff at Christie's are said to be worried about today's sale.

The first signs of trouble came on Friday when an auction of art at Sotheby's in London, timed to coincide with Frieze, fell far short of what was expected. The estimated sales total of £30m had been low, but the actual figure was £22m. Even Andy Warhol, one of the most bankable artists of the 20th century, failed to live up to expectations: a series of skulls expected to fetch at least £5m went for £4.3m.

"People won't be surprised if Frieze is quite muted," said Mr Dupplin. The global market is all but dead already, he said, except for buyers of "trophy art" whose fortunes have previously seemed unassailable. If they stop bidding, prices will plummet.

Among them is the Russian oligarch Roman Abramovich. Earlier this year he paid £17.2m for Benefits Supervisor Sleeping, making Lucian Freud the highest-priced living artist at auction. He also made the late Francis Bacon the most expensive artist ever by spending £43m on Triptych (1976). So it seems reasonable to expect he might bid big for a portrait of one of those painters by the other.

The only other picture of its kind was stolen in 1988 and has never been found. This one was begun in the winter of 1956, but abandoned after Bacon refused to continue with the sittings. If it doesn't sell well, it will be proof that even the trophy hunters are cutting back. If it does, then a surge in confidence will keep the market going. For now.