Well Superpilot, Flybe, alone has 45-50 Q400's. Then you've got Loganair, Stobart, Aurigny, Blue Islands, Atlantic and Eastern, probably others I've missed too. That must be 150+ turboprops and they used to be a great way to enter the airlines, get hands on flying and progress to bigger planes that provide bigger pay cheques.
Now things have changed and thanks to cadet schemes, these turboprop jobs are not as good a stepping stone as they used to be. Why take on on an experienced TP pilot (or regional jet for that matter) and pay them well, when you can take on somebody with no experience but willing to pay insane amounts of money for "tagged" training? P2f and its derivatives have killed it as a progressive career in the UK.