Aha! Another soul packing for Canada.
I had a chat with a couple of Canadian accountants on this very issue; there
is an agreement. The pension will be taxed in UK, but as it will be the only income, it will be at the lower rate. It will not be taxed in Canada and what's more, as taxed oversees earnings, current regulations mean that the Canadian's will ignore that net income as part of your total income for their tax purposes.
Watch out however for the gotcha concerning the index linking of you pension, as this does not apply until your 65th birthday if you emigrate to a commonwealth country...
