The 'easy way out' for London is to co-erse any relatively low performance light aircraft to leave controlled airspace before it reaches the complexities of the London TMA
I am not privy to what the controllers see on their radars but over many trips through there I have never seen any evidence for any difficulty of having ~150kt traffic in that airspace, at some reserved-ish lower airspace level like say FL100.
Accordingly, I suffer from a continued difficulty reconciling the "packed airspace" claims that come from various ATCOs on the pilot forums, and Eurocontrol officials in their presentations, with
reality, where I am flying at say FL100-150 and all I see is contrails at ~FL300+, and the occassional "737" at my sort of level but so far away I can't tell if it is a 737 or a 747.
This is the kind of thing.
The same is echoed across Europe, e.g. flying around Brussels, Frankfurt, etc.
I am sure that when LC used to dump people out of CAS it was due to laziness, or maybe some dodgy laid down procedures. Not because they could not achieve separation. UK IFR ATC are up with the best there is. Only the USA does better, in the sense of a "can do" attitude.
Such action should be compensated by hefty rebate on route charges!
Of course, the forum ATCOs are quick to point out that < 2T one isn't paying so one is getting a free ride, ergo any expectation of customer service is unjustified.