Only pay the interest
With an interest only mortgage your monthly repayments only pay the interest on your loan. You will still have to pay the whole amount you originally borrowed at the end of the mortgage term.
As the monthly payments are for interest only, it is important when comparing the total monthly cost of an interest only mortgage with those of a repayment mortgage, to include the money put aside as savings.
How it works
You will need to make separate arrangements to make sure you can pay the final lump sum. This will normally be some form of investment such as an ISA, endowment, PEP or pension.