Define what's a professional gambler? I've worked in betting and I've seen people consistently printing millions of pounds a year with remarkable stability ove

Define what's a professional gambler? I've worked in betting and I've seen people consistently printing millions of pounds a year with remarkable stability over the years (I was myself running an exchange). However they may not fit the popular image of an older man addicted to horses and drinking. They're professional working at (small) companies doing that activity full time.