An enlightening thread.
As has already been mentioned the root of this problem is communication, and at least we are doing that here!
The original post seemed to point a finger at a/c arriving into LTN and STN, and in particular the B737. Well that's my patch so I'm listening up! I here the gripes from ATC here, I'll take note and pass some of these comments on to my colleagues.
I think the point has already been made that there is no such thing as a standard speed in the descent above FL100. There is great variation between company SOPs, a/c types and cost indices flown. So the assumption that everyone is flying at 300kts is ill-founded. If you have a 747 at 250kts and a 737 at 320kts catching him, can you not tell from the vector on your screen? If you need them to alter speed either up or down, just ask. After all, you are in control of your bit of the sky! If he is unable to do so he should tell you.
Alternatively, we could report our speed to each new sector, but I think you'd agree that would be rather over-the-top!
Regarding the intermediate approach phase, there is an increasing amount of standardisation here. 210kts initial vectors, 180kt final vectors and 160kts to 4nm on the glide, or something similar. However, I believe a 747 is almost falling from the sky at 160kts, whilst my little 737 requires some swift deceleration to be stable by 1000' agl,(Company SOP), and can prove impossible. But again communication is the key.
ATC fam. flights would be great, but as KRISKROSS says, in our company nobody enters the flightdeck anymore except for the operating crew. I read another thread on Prunne recently that spoke of a DfT / CAA ruling banning non-crew from the flightdeck. Does anyone know where I can obtain a copy of this ruling?