Originally Posted by
NickB
Perhaps it might be worth going via landside at those times.
I actually wondered that several times as you can then use the North fast track. However, the early part is also quite heavy both on immigration (sadly, the fact that French passports always seem to fail the automated gates can mean a longish queue!) and on London origin security which might make the time savings minimal. Around 9/10 though I think I might do exactly that and hope for the best.
I read somewhere that some people had managed passing security at T5B even if their connection was not from there, but I am unclear as this works as when I asked I was refused with the explanation that it is only for people with confirmed departure from T5B/C.