I have always found that "Speedbird123 After the Aer Lingus A320 on the north side departs line up and wait" takes up far more R/T time than "Speedbird123 line up".
From a pilot's viewpoint - we are all cleared to the holding point and often join the que some distance before the holding point i.e. we are cleared to a position on the airfield but have to wait until aircraft ahead move out of the way before we get there.
When a runway is used in departure only mode why can we not be told to line up when the threshold is occupied by a departure i.e. when the Aer Lingus in the above example enters the runway, we are told to line up.....same effect as the "clearance" to the hold point...we get there when the other guy moves.
It seems that the current situation of conditionals is effectively doing that because most flights creep forward past the hold bars and into position as soon as possible after the previous flight departs for the reasons given previously.
For mixed use runways simply say "BAW123 line-up" as the lander passes the threshold. Seems to work other places.
If conditional clearances are such an essential requirment why have never heard "BAW123 after the landing B737 vacates cleared take-off"
One way of reducing workload at Heathrow would be the introduction of a requirement to contact the ACC imediately after departure without the requirement for the tower to initiate the frequency change as has been successfully done at other places for years. That alone would reduce the R/T load by 1 call per flight which is lots per day!
Regards,
DFC