I'm getting a company pension from a UK company. Which box number? in 2018 Posted April 13, 2018 · Report reply Thank you, I'm sure this is the right answer. I doubt that my pension would be "not taxable" in either country, because in the UK, as in Canada, the principle is the same: you put money aside tax-free when you're working, and then draw it and you do pay tax when you're retired (hopefully at a lower rate). The only thing that might be relevant for other people, is that the UK will tax the pension 'at source' if it exceeds a certain amount (I think it's £11,500). If that happened, then there might be some arrangement to avoid double-taxation. However, my pension is lower than this figure, so I won't pay anything in the UK anyway.