Re: 250kts on departure
GWH
Yep - point taken however a lot of the time we keep EGKK Lam Deps at low speed - this helps them outclimb the Biggin stack and also means the radius of turn is smaller as it is less of a turn back to keep you clear of EGLL traffic inbound from the north east. (And turn radius is less)
That is us using speed as a tool - we are about to be denied using speed as a tool in different ways for different A/C.
Just to clear that up GWH as it may seem we are talking at cross purposes, I understand your true ROC may be less, but in ATC terms, although we may want a high fpm rate, what we are looking at in reality for us is your actual feet per mile rate. When you have accelerated, we are still judging your climb rate on how far away your traffic is.
We both want a good climb at times, but interpret it in different ways!