But in terms of price, they were eclipsed by the top lot, a bright canvas entitled No 15 painted by Russian-born artist Mark Rothko, which was sold for £1.65m.

Bacon worked for 30 years at his Kensington studio

The Bacon paintings are regarded by critics as great examples of his most existential and angst-ridden work.

Bacon's 1954 work, Man In Blue VII, was sold for £707,750.

The piece is the culmination of a series of pictures Bacon painted while staying in the Imperial Hotel at Henley-on-Thames, near the house of his lover, Peter Lacy.

Head, painted in 1962, the year Mr Lacy died, depicts the head of a surgeon with a lamp strapped to it. It was bought for £311,750.

Violence

Portrait of Man with Glasses IV, from 1963, was sold for £894,750, twice the expected price.

It depicts a man whose distorted face looks as if it has been very badly beaten.

Bacon was one of the last century's most successful artists, earning about £14m before his death in 1992.

Studies of the Human Body sold for £6m in New York

Violence was prevalent in much of his work, reflecting the turbulence of his own life.

His relationship with Mr Lacy was punctuated by fights that often resulted in Bacon's canvases being vandalised.

A series of three paintings by Bacon of his long-time partner, John Edwards, sold for £3m in 2001, and Studies of the Human Body sold for £6m in New York last year.

In total, Post-War Art fetched £7.4m and included work by Erika Klein and Andy Warhol.