Owning a 1br flat in London probably makes you a millionaire at this point.  Doubt you can retire off that, but you can sell and move somewhere with lower housing and other costs of living.  In fact, a large portion of these sales may be people retiring to another country where they can better utilise that capital/ protect their childrens inheritance. 

 Well, that's still not applicable for younger folks.  For them, very few places accept poor migrants. And they can't copy millionaires. That's why the world is so lame these days. Gotta kill boomer kikes.