I am a factual resident of Canada, however my main income is from work in the UK. My UK employment income is taxed at source by HMRI, but I must declare my foreign income when filing Canadian taxes with the CRA. According to the Canada-UK tax treaty I believe I should not be double taxed.* Within the CRA self assessment tax filing, I can indicate my foreign income and taxes paid on that income, receiving a foreign tax credit with form T2209. However, it still appears I am required to pay taxes to CRA on this income. Should I be declaring all of my foreign income on line 25600 as 'exempt foreign income', since it has already been taxed by the UK? Would this be the best method for avoiding double taxation, or indeed should Canada additionally tax this foreign income as I am factually resident in Canada?
* See for instance Article 15 Dependent Personal Services: "salaries, wages and other similar remuneration derived by a resident of a Contracting State in respect of an employment shall be taxable only in that State ...".
You would have to check the UK/Canada tax treaty or talk to someone knowledgeable about it to verify if the income is 'exempt foreign income'.