 Complete the following phrase:  The real-life ship used in the film was HMS Leamington. Built in 1919 as the USS Twiggs, a Wickes-class destroyer, she was one of the last post-war survivors of the 50 elderly four-funnelled destroyers provided in 1940 by the USA as part of the Destroyers for Bases Agreement: also known as The Fifty Ships that Saved the World. She served on convoy duties, including as an escort for the ill-fated 