In Europe, 50 years, until 'Love Me Do" and "PS I Love You" turn 50, at which time copyrights will not doubt be extended.
In the US, Mickey Mouse sets the limits. Copyrights will continue to be extended to cover Mickey Mouse, although there were a couple of Americans prior to Mickey Mouse who also made significant contributions.
That's copyright law in a nutshell. Stupid, I know, but that's how it works.