Please Can Anyone Help Me Find The Name Of A Film Starring Jack Hawkins? It Was Made In The 1970’s, Or Possibly The 1980’s. Hawkins Starred As A WWII British Spy In Berlin Posing As A German General.

Unfortunately, don’t really know anything about the content/plot or other actors in it, except Hawkins’ character collects antique clocks or watches and there’s an antique shop he frequents where the owner’s also a spy. Ends with Allied Forces taking Berlin and Hawkins has to shout codeword to them so they know he’s British spy not German and don’t shoot him. This is a desperate quest so I can buy the film for my mum who saw it when it came out and loved it, but can’t remember the name! Please help! Many thanks!