Well a time card from when they checked in would be better.
You wouldnt believe the amount of passengers that check in then bugger off somewhere then turn up close to departure time too.
But still thats no excuse, I have to say im normal quite lucky by the sounds of it, although last time i went out from LHR it was T1 in January i queued up for 11 minutes and it was 11 minutes as i timed it for the supervisor on duty. however it has got alot worst since then, as ive been hearing from the guards themselves,
None of the other BAA / Non BAA airports seem to have the problem so it must be a Heathrow Managment problem.
I think T4 is crap because they have one archway for 2 xray machines which creates a bottleneck too.