A number of things are different in the UK compared to other European countries.
NATS is a private company, for a start. This puts a totally different slant on how services will be funded, etc. Most (all?) countries in Europe have a national ATC service which they maintain well, for national security reasons if not others, and this is why you find when you fly into France suddenly everything changes; you get a radar service everywhere, every unit you call up has your flight plan to hand, even small airport towers have a radar data display, etc.
The UK implements a near watertight division between VFR and IFR/CAS services. The latter gets the usual seamless control from London Control, etc, while all other traffic is kept separate and gets a FIS (which does not provide a radar service so few pilots call it up) or the occassional radar service from a LARS unit. LC will absolutely not provide any service to VFR traffic, or IFR traffic which is below their CAS layer (loosely speaking below FL080 or so).
As suggested above, this results in a situation where you have absolute control and right next to it you have airspace (which quite often is shaped into a bottleneck - even better for PPL-level navigation skills as trained in the UK
) in which you have traffic which is not only uncontrolled but also totally unknown, without transponders in most cases and often without radio. With the typical airport CAS, it takes just a few minutes at say 100kt to enter the CAS and end up overhead the said airport and bring operations to a halt.
Most if not all of the IFR/OCAS airspace is Class A; not for any good reason but it has been that way for a long time. It should really be Class B or C. Class A of course prohibits VFR implicitly.
The UK has the advantages of lots of Class G and the ability to fly IFR in it, even non-radio i.e. without ATC clearance or any flight plan. One can fly all over the UK in Class G. Of course this works only if the pilot can actually navigate; many cannot and they bust bits of CAS. But nothing can be done about this because the training is so poor and refuses to embrace modern navigation technology.
The extensive Class G, with its relative lack of a useful service, works well with the UK model of "user pays" because GA (below 2000kg) does not pay so it doesn't "deserve" a service so it does not get one. This incidentally is why the IMC Rating works so well in the UK - it is a "DIY flight in IMC, with no service" kind of thing.
Also, UK GA has been historically quite effective in restraining the growth of CAS. This has been achieved successfully no doubt due to the fact that no ATC service needs to be delivered OCAS