A mortgage protection (decreasing) policy will suffice as long as you don't extend or increase your mortgage. The new mortgage provider will accept the existing policy. A convertible term policy has the added advantage of not decreasing over the term and the convertible option will allow you to extend the policy at the end of the term without the need to provide further medical evidence or allow you to change the cover midterm (who knows what lies ahead, if you needed to change your life cover down the road, you cannot change an MP policy. If you developed a medical condition in between policies it could be problematic). Usually there isn't a massive difference in price between an MP & CT policy, but if you want to keep costs to a minimum than the MP policy should suffice, at least in the short to medium term.