Goofs

When Catrin Cole exits an Underground Station an Air Raid is starting and Air Raid Sirens are sounding; however they are not broadcasting the rising and falling note of the "Air Attack Warning", but the constant high pitched note of the "All Clear" which was / would be sounded after danger had passed.

In the newsreel footage the token American is seen to run toward his waiting Spitfire, he climbs into a Hurricane, waves to the camera from a Spitfire, takes off in a Hurricane then after his mission he lands and walks away from a Spitfire! American pilots who joined the RAF and didn't join the RCAF were assigned to one of the three Eagle Squadrons. Given that the movie is set in 1940 and the only Eagle squadron established at the time was 71 Squadron, so this young hero, must have been in 71. It is true that 71 did fly both Hurricanes and Spitfires, but they didn't start flying Spits until August 1941.

Ju87 siren heard in sound of approaching bomber. Ju87's did not bomb at night during the Blitz.

Model of Ju87 has only two propeller blades, rather than three.

At the start, Arterton's character is told: "A page of script equates to a minute of screen time, or roughly 80 yards of celluloid."

35mm cinema film is composed of 16 frames per foot, and runs at 24 frames per second, so a minute on screen is exactly 90 feet or 30 yards. Eighty yards would be 240 feet, or 2 minutes 40 seconds.

For a film about film-making, this is a ridiculous mistake to make.

Set in the year 1940, and when filming on location correctly shows what Technicolor's three-color camera looked like, but incorrectly failed to show what the Technicolor camera looked like when used on the sound stage. The early days of the Technicolor three-color camera invented in 1932, the three-strip 35mm Technicolor camera was barely a manageable size for a camera on location, and is very easily recognized with its extra wide film magazine (painted pale blue), because the camera has three 35mm black and white film reels shooting the same image in parallel. However to use the Technicolor camera on a sound stage, immediately required the camera to be fully encased in huge sound-damping equipment to muffle the very loud operational noise that the camera made, increasing the weight of the camera and increasing the size by more than 300 percent.

1930s/40s Technicolor cameras needed ridiculously large amounts of artificial light in order to get a good result (hence why most early three colour technicolor films were studio bound). Yet nowhere during the location shoots of this film do we see the huge arc lamps needed for Technicolor filming..

A CCTV camera is clearly visible in a scene where the main character is running down a London street. That scene is used as a still for the trailer.

One of the films shown has an "SMPTE Leader". In 1940, the Society of Motion Picture and Television Engineers was still known as SMPE.

At 24.41 as she runs down the street you can see a modern street light in the back ground.

Breeze blocks visible in shot - not yet invented.