What is the difference between a repayment mortgage and an interest-only mortgage?

A repayment mortgage is guaranteed to pay off your mortgage by the end of the term if all payments have been made.
With an interest-only mortgage, you only pay the interest on the loan each month – leaving the loan itself outstanding. At the end of the term, you still owe the money you borrowed, so it is important that you have a strategy in place to repay the borrowing.