The sale price was almost four times the top pre-sale estimate and beat the previous record for a Churchill painting, which was just under £1.8m.

The Tower Of The Koutoubia Mosque, painted in Marrakesh during World War Two, was sold to an anonymous buyer.

A Christie's spokesperson called it "Churchill's most important work".

"Aside from its distinguished provenance, it is the only landscape he made during the war," the spokesperson added.

Churchill, a keen artist, took inspiration from the Moroccan city and painted The Tower Of The Koutoubia Mosque oil work following the Casablanca Conference in 1943.

He went on to give the finished piece to fellow wartime leader, US president Franklin Roosevelt.

Frenzied bidding at Monday's sale, much of it over the phone, led to the auction gavel coming came down at the record £7m sale price, smashing the pre-sale expectations of £1.5 to £2.5m.

Christie's said the sale figure with commission was more than £8.2m.

Two more of Churchill's paintings also went under the hammer, with the three works together fetching £9.43m.

Before entering politics Churchill was a career army officer and started to paint relatively late, at the age of 40.

He found a passion for the translucent light of Marrakesh in the 1930s when most of Morocco was a French protectorate.

Churchill created his painting from the balcony of the city's Villa Taylor, beloved by the European jet set of the 1970s, after the historic conference in Casablanca, where the allies declared they would accept nothing less than Germany's "unconditional surrender" in the war.

The painting depicts the minaret of the mosque behind the ramparts of the old city, with mountains behind and tiny colourful figures in front.

'Soft power'

After the US delegation left the conference, Churchill stayed on an extra day to paint his work. He then sent it to Roosevelt for his birthday.

"This is Churchill's diplomacy at its most personal and intense," said Nick Orchard, Christie's head of modern British and Irish art.

"It is not an ordinary gift between leaders. This is soft power, and it is what the special relationship is all about."

A second Churchill landscape, Scene in Marrakesh, painted on his first visit to Morocco in 1935, previously sold for £1.5m.

Jolie's former partner Brad Pitt is known to be an avid art collector and, during their marriage, the couple bought some notable works, including some by Banksy and Neo Rauch.