By my rough guess there are probably less than 50 UK registered turbo-prop or commercial 'light' aircraft flying with UK airlines today. Compare that to the number of jet aircraft of which there are over 500!
I don't know who flies them, but the UK civil aircraft register lists:
BA ATP = 17
ATR 42/72 = 8
Twin Otter = 6
Q400 = 45
Beech 1900 = 3
Saab 340/2000 = 30
Dornier 228 = 3
Dornier 328 = 5
JetStream 31/41 = 30
Metroliner = 1
Short 360 = 1
PC-12 = 1
Lockheed Electra = 2
Total Commuter type or large turboprops = 152
Then there are 40 Islanders, 38 Piper Navajos, 77 Cessna Citation, 8 BAE-125s, 16 Bombardier Exec jet, 10 Lear jets, 24 Beech 200/300, 12 GulfStream jets.....
In a few minutes of searching the UK civil aircraft register, I have listed over 350 UK registered aircraft that are flown by professional pilots.
There are also about 150 lighter commuter jets such as the Emb 135/145/175/195 and the CRJs.
That comes up to over 500 professionally flown aircraft without counting a Boeing or an Airbus. There are probably many others.
Not to mention that this is just the UK. All of the EU is open to UK pilot as far as I know.....