A current account mortgage enables you to operate your mortgage borrowing, savings and current account through one account. Essentially, it is like having a large overdraft. For example, if you had a mortgage of £150,000 and £10,000 in your account, your balance would show as £140,000 in the red and this is the amount you would pay interest on. 

By paying your income and savings into the same account as your mortgage you're reducing your mortgage balance. This could save you a fortune over time in interest and potentially reduce the term of your mortgage. 

Normally, you are required to pay your salary into these type of accounts.

Any cash you pay into the account, such as your salary will reduce your outstanding mortgage debt. Therefore, if you are disciplined you can save on the amount of interest you repay and the length of your mortgage. Most lenders will show you on a regular basis whether you are ‘on track’ or above / below track with your payments.

An offset mortgage is an extension of the current account mortgage principle. You keep your balances e.g. mortgage, savings, current account etc in separate accounts but all balances are offset against each other,  with potentially substantial interest savings.

With some products you have the ability to make underpayments – this means if in one month you have an unexpected expense you can pay less off your mortgage - or make over-payments to clear the debt sooner.