Originally Posted by
EdmFlyBoi
LHR wasn't seamless connecting when I was there a week ago. Certainly not as bad as Pearson, but LHR doesn't seem to have the ability to totally avoid some form of a lineup when connecting international to international. There was a fairly long line for the security queue to make this kind of transfer (though not nearly as bad as the UK border).
That's a problem at a lot of airports these days, and compared to the question I was responding to about dealing with a terminal switch, or other huge inconveniences like clearing UK immigration, even a "fairly long line" at security probably passes for "pretty seamless" these days.