I get them. The UK, to the best of my knowledge, does not specifically stipulate the length of time you need to spend in the UK in a defined time period (such as two years in five) to keep your PR but you do need to be able to prove (if asked to) that your life is connected very substantially to the UK. Are you talking of indefinite stay/Leave to remain permanently in the UK or the Nationality? Because, if you have the nationality there is no rule as to how long you have to have lived in the country nor to have stayed outside. You may stay as long as you wish anywhere in the world and still return to the UK. (provided you are not ripped of the status (which can be done in some circumstances) or you give  up the Nationality intentionally for one reason or the other "It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change". To become successful you must be a person of action.Merely to "know" is not sufficient.It is necessary to both know and do. I might be in similar situation soon. However reading through a number of posts it has lead to confusion. Some say one need to contact the Canadian Embassy in London to let them know of the change in nationality prior to entry to Canada. Some recommend contacting the CIC in Canada. And others recommend travelling with