It was the turning point of World War II in Europe. In June 1944, Allied troops under the command of General Dwight D Eisenhower, were preparing to land on the beaches of Normandy and start a last-ditch fightback against Nazi Germany. But one thing potentially stood in their way and it was something they couldn’t control. The weather.

The outcome has gone down in history, but the impact of the weather is rarely more than a footnote. Pressure, which is released in cinemas this week, takes us behind the scenes of the days before the landings, when Britain’s chief meteorological officer, the soft-spoken James Stagg (Andrew Scott) goes head to head with senior military, including Eisenhower (Brendan Fraser) and General Montgomery (Damian Lewis), the leader of the British forces. Asked to deliver what could be the most significant weather forecast in history, his prediction is not what his superiors want to hear: bad weather could devastate the invasion, but a delay risks German intelligence discovering their plans.

In the exclusive interview below, we sat down with David Haig, author of the original play which inspired the film and co-writer of Pressure’s screenplay, and Damian Lewis, who plays the legendary and formidable Montgomery. Haig describes how the story of an unsung hero has been part of his life for a number of years – he also played James Stagg on stage – and how a play which was set in one room has been expanded into a film with powerful exterior sequences. Lewis reflects on playing one of the most familiar faces of WWII and how, despite being a hero to his troops, is a forceful opponent for both Eisenhower and Stagg in the hours before D Day. He sums him up as “a tricky b*gger!”

You can watch the interviews below.

Pressure is in UK cinemas from 9^th September. Read our review here.