Sotheby employees in London display Pablo Picasso's painting La Lecture, which sparked a brief but tense bidding war at auction Tuesday. ((Matt Dunham/Associated Press))

A heated competition between bidders ended with Pablo Picasso's La Lecture soaring past expectations and fetching more than $40 million in London.

The 1932 portrait of Picasso's young lover and muse Marie-Thérèse Walter sparked a brief bidding war between seven interested buyers at Sotheby's impressionist and modern art sale on Tuesday evening.

An anonymous telephone buyer triumphed at the British sale. After approximately six tense minutes of rapid bidding, the final hammer price was £25.2 million (about $40.2 million Cdn, including auction house premium).

Le Lecture carried a pre-sale estimate of £12 million to £18 million (about $19.1 million to $28.7 million Cdn).

The painting, which depicts Walter asleep in an armchair and a book left open across her lap, hails from the cubist artist's "annus mirabilis" (year of miracles), when he created some of his most celebrated works and cemented his place as a modern master.

With files from The Associated Press