Thank you for the clarification Boffin1
I tried with a red LED and 12 Ohm emitter resistor which give me 350 mA collector current. I am not sure how to calculate it.
I think you always have to do some experimentation regarding the base resistor as the Hfe has a large spread, and depends on the collector current
From the datasheet:
hFE
VCE=1V, IC=100mA 100 - 630
VCE=1V, IC=300mA 60
It is a very nice circuit. Earlier I have used LM317 for this kind, but I have a lot of BC337's so this is a cheep solution.