Michael Caine appears briefly as one of the prisoners on the train. As Violette starts to escape he leans forwards and calls out for water.
Virginia McKenna lost 5 pounds in the 92 days she spent filming.
After firing machine guns, jumping from a parachute training platform, spending weeks learning unarmed combat, wading through an ice cold lake at night, spending many hours doing physical jerks and cross country runs, there was one thing that made actress Virginia McKenna scream with terror: a cockroach in a pile of vegetables.
At the end of filming party, actress Virginia McKenna served ice-cream carved from a four foot high model of herself as Violette complete with sten gun.
Of the 92 days she spent filming, actress Virginia McKenna only had two days off from the rigorous schedule which included getting up at 5:30 each morning. The two days off were to marry Bill Travers and have a very brief honeymoon.
Technical advisor Leo Marks was in charge of the codes and ciphers for all SOE agents during the war - when he was only 20.
Technical advisor Major 'L.P. Fernandez' was one of Violette Szabo's instructors.
The director and producer both wanted a double to be used for the jump from the parachute training tower, but Virginia insisted on doing it herself. Slowed slightly by a wire (as are all trainee parachutists) she landed with a professional-looking roll on the mat below. Picking herself up she smiled and said "That was fun; I'd like to do it again."
The London Transport, double-decker bus was borrowed from the London Transport museum and fitted with "anti-blast" netting on the windows and "blackout" covers on the headlamps. It was driven by John Kirkup who worked as a fitter for London Transport.
Wildfrid Bonnin, the public health inspector for the London Borough of Lambeth, went to inspect the mobile canteen catering for 100 workers on location. He was pleasantly surprised to discover what they were filming as he used to be an air raid warden with Violette's father.