When Wing Commander Mason (Dirk Bogarde) removes Pilot Officer Greeno's name from the crew list on the blackboard, he tells the Adjutant that "One one eight squadron is standing down". In fact the squadron's number in the film is one eight eight.
When Tim arrived by himself at the pub he lights a cigarette, then removes some tobacco from his tongue with his fingers. He rubs his fingers together and moves the cigarette pack. As we cut to the next shot he rubs his fingers together again and moves the pack again.
Just before the RAF officers in the car meet Eve Canyon, played by Dinah Sheridan, standing next to her broken down car, William Sylvester is sitting next to the front passenger door. Then suddenly, William Sylvester is driving and Dirk Bogarde who wasn't in the car in the previous shot, is now sitting next to the front passenger door.
In the scene depicting the take off starring Bill Kerr as the Australian pilot, he starts the aircraft up with the phrase "contact port outer". This is incorrect - the Lancaster would have started with the port inner engine as this drove the hydraulics which controlled the turrets etc.
When Mason and the American board the aircraft for the last mission they are not wearing any flying gear - only normal uniforms. At the altitude flown they would have risked frostbite and hypothermia due to the cold.