There are three other types of mortgage that can occasionally be found in the UK:

Low start mortgages
This is like a repayment mortgage, but with a difference. In the introductory period, only interest is paid back to the lender and not any of the capital outstanding. After this period, the repayments start in earnest. The total amount of interest and repayments over the life of the year are higher than with a normal repayment mortgage, but this sacrifice can be worth it if you need to severely restrict your outgoings during the low start period.

Deferred interest mortgages
Interest is not paid during the discount period. When the discount period is over, the accumulated interest is added to the original loan. Some lenders add this interest to the total of your loan to give a new loan figure and new interest payments. Others calculate your interest payments on the original loan as normal and then spread the repayment of the deferred interest over a set period of time. The latter method is better for you, as adding the deferred interest to the loan means you end up paying interest on the deferred interest!

Equity linked mortgages
Similar to the method used by housing associations except it is the lender who takes a stake directly and not the housing association. The lender takes ownership of a stake in the equity of the property. This means that they lend you less than the full amount that is required to buy the home. Interest is only charged on the amount that they lend you and not on the full value of the property. When you sell the property, the lender receives payment in proportion to the amount of equity that they own, and therefore benefits from any increase in the price of the property.