A 'double' self-portrait by the Dublin-born artist Francis Bacon is expected to sell for €23 million – or more – at a Sotheby's auction in London on Tuesday evening.

Two Studies for Self-Portrait, which dates from 1977 when the painter was aged 68, is described as "a profoundly intimate portrait, starkly evoking the artist's inner turmoil".

Since his death in 1992, Francis Bacon has become the world’s most expensive artist at auction and his paintings routinely sell for millions

He is famous for his abstract, and often violently contorted, images of the human body. The two-panel painting – known as a diptych – last sold at auction in London in the early 1990s for £353,500 (€474,000). But, during the past decade, prices for his work have soared and the top pre-sale estimate is now £18 million (€23 million).

In November 2013, Three Studies of Lucian Freud, a triptych portrait by Bacon of his friend and fellow artist sold at Christie's, New York for US$142.4 million (€114 million), setting a new world auction record price for any work of art.

Francis Bacon, whose father was an ex-British Army officer and racehorse trainer, grew up in Co Kildare but fled to England as a teenager and worked in London all his life. Although Irish-born, he is classed as a British artist in the international art market.

The former British Prime Minister Margaret Thatcher once described him as "that man who paints those dreadful pictures".

Bacon painted numerous self-portraits in later life and, asked why, famously said: “People have been dying around me like flies and I’ve had nobody else to paint but myself … I loathe my own face and I’ve done self-portraits because I’ve had nothing else to do.”

Oliver Barker of Sotheby's said: "Of all the subjects he depicted, it is the self-portraits – painted with an almost obsessive intensity – that bring us closest to the artist. It's this extraordinary intimacy and power, together with their rarity, that make Bacon's self-portraits so irresistible to collectors."