I changed careers. My starting salary on a 737 is around £32k, plus they pay me back my TR bond over 3 years, so it looks like a salary of £38k. (If you forget you forked out for the TR!)
Guys who were on my TR course are mostly from TP operators, such as Flybe and Eastern, and their pay ranged from £18k-25k. The EZY folks who were with me at CTC all came from TPs and Air Taxi companies too, with similar salary levels, although some were captains with the likes of Aer Arran and Air Alantique and were on £40K+.
If you are lucky, you won't have to pay for a TR, but only a few operators, such as BA/BMI seem to do this, and you have to go to an integrated school to get an interview with those companies. But saying that, BA starting cadet salary is pretty bad compared to jet operators elsewhere.
I paid considerably more than £40k for my modular training.
Now that CTC have lifted their daft age restriction, I would recommend everybody to have a go with them first, if not for their ab-initio training, then certainly for their AQC - when it re-opens!