A papal portrait by Irish painter Francis Bacon has been sold at Christie's in London for €21.2m.

It is a record for a work by Bacon sold at auction. The painting - entitled 'Study For Portrait II' - has not been seen in public for over 40 years. The identity of the new owner is not known.

The hammer price was €18.9m, but the auction house's commission brought the total purchase price to €21,198,240.

The painting, which was completed in 1956 and is one of a series papal portraits, is said to be the most important work by Francis Bacon to come on the open market.

It has always been held in private hands, and the successful bidder left tonight without wishing to be identified.

Francis Bacon was born in Baggot Street in Dublin in 1909 and brought up in Co Wicklow. He left Ireland when he was in his teens. He died in Madrid in 1992.