No modern depiction of Winston Churchill, be it at the cinema or on the television, is complete without his trademark Homburg Hat, fastened bow tie and, of course, smouldering cigar.

Yet the makers of an upcoming Churchill biopic have been criticised by historians after they felt it was necessary to warn viewers that scenes with the former prime minister smoking a cigar are "based solely on artistic consideration".

The film, titled Darkest Hour, is set in 1940 and stars Gary Oldman as the wartime leader - a role for which he has been acclaimed by critics.

Churchill is pictured smoking throughout the film, which is scheduled for release in the UK next month.

In the opening scenes his face is lit by a cigar as he sits in a darkened room before viewers watch as he chomps away while greeting a five-month-old baby on the London Underground.

Historians and biographers have criticised the disclaimer, which appears in the final credits, which also alerts viewers to the "serious health risks" that accompany smoking.

“The depictions of tobacco smoking contained in this film are based solely on artistic consideration and are not intended to promote tobacco consumption," the health warning begins.