Finding yourself in opposition in the House of Commons can be uncomfortable for those who once led the nation, especially for someone also credited with a vital military victory. So it was for Winston Churchill . But in 1949 he was consoled with the extraordinary gift of a French impressionist masterpiece: Claude Monet’s depiction of the Palace of Westminster, wreathed in heavy mists.

This generous present, now worth many millions, was accompanied by a note to Churchill wishing that “the fog that shrouds Westminster”, ruled then by Clement Attlee’s Labour party, would soon lift. The hazy study of the facade of Westminster over the River Thames, completed in 1902, is now to be one of the stars of a landmark exhibition, Monet and London, that will reunite many of the impressionist’s most famous images of London for the first time in 120 years. The former prime minister’s picture is one of only two Monets in British ownership featured in the show at the Courtauld gallery on the Strand next month and it has been newly restored for display, with the removal of a layer of yellowing varnish, applied later to the canvas.

“Churchill’s love of Monet dates right back to when he was first studying painting himself in the 1930s, after he was tutored by the portraitist John Singer Sargent , who had painted his mother,” said Katherine Carter, curator at Chartwell, the politician’s former home in Kent. “Sargent had suggested Churchill start out by copying other great ar.