Tutu, a long-lost portrait by Ben Enwonwu of the Ife royal princess Adetutu Ademiluyi – described by Booker Prize winning Nigerian novelist, Ben Okri as Africa's Mona Lisa – set a new world record for the artist's work at auction, achieving £1,205,000 at Bonhams Africa Now sale in London today (28 February). After a 20-minute bidding frenzy, the work sold to a bidder on the telephone. The result makes it the most valuable Modern Nigerian painting sold at auction. It had an estimate of £200,000-300,000.

Bonham's Director of Modern African Art, Giles Peppiatt said, "The portrait of Tutu is a national icon in Nigeria, and of huge cultural significance. I am delighted that it generated so much interest and set a new world record for the artist. It is very exciting to have played a part in the discovery and sale of this remarkable work."

Enwonwu painted three versions of Tutu during 1973-74, and the image became a symbol of national reconciliation for a country struggling for unity in the wake of the Nigerian-Biafran conflict of the late 1960s. All three paintings had been considered lost until Giles Peppiatt discovered the current picture in a London apartment, where it had hung for the past 30 years.

Writing in the spring edition of Bonhams Magazine, the Nigerian-born Booker Prize winning novelist Ben Okri, described Tutu as Africa's Mona Lisa. He said, "It amounts to the most significant discovery in contemporary African art in over fifty years. It is the only authentic Tutu, the equivalent of some rare archaeological find. It is a cause for celebration, a potentially transforming moment in the world of art."

Enwonwu's work Negritude, also painted in the 1970s, was sold for £100,000 in the same sale.

In a pioneering move, the sale was broadcast live to a Bonhams auction event in Lagos, where bidders were able to participate in real time.