Can I work long term in Canada on a British passport?
No special status for British or Commonwealth citizens in Canada. You need to go through the regular immigration process. It helps you in terms of the Express Entry program that you (presumably) are fluent in English, since 24 out of 100 points of preselection are awarded based on English (in your case) fluency based on IELTS score. If you are married and your spouse is fluent in English then youd get 5 points based on your spouses IELTS score.