The flexible mortgage is a relatively new type of mortgage, or at least new in the UK. It was invented & has been used in Australia for many years, but is now growing in popularity in this country as more and more lenders adopt it.
A bit of background
The traditional UK mortgage has been with us for many generations. It was designed with the assumption that people had full time employment and could therefore cope with set monthly payments for a 25 year period. However, as many people have discovered, the traditional mortgage does not always cope well with modern employment trends, such as contract working, self employment, job sharing and part time work.
This is where the flexible mortgage comes in. It has the facility for both over and underpayments built into the loan. What this means is you can overpay your mortgage when finances allow (pay rise, bonus, an inheritance etc.), and then, providing you have made overpayments in the past, underpay when finances are tight (job loss, change in circumstance etc).
A Generic Example
If you overpay your loan by £50/month for say five years on a flexible mortgage, that cumulative amount is then made available as a cash reserve for you to draw on at any time during the remainder of the mortgage term. This cash reserve can normally be drawn on for such things as, taking payment holidays or making large purchases. Indeed some lenders actually issue the borrower with a cheque book and encourage them to use the account as an all encompassing bank account. However the amount you can withdraw is limited by the original sum of the loan.
The main benefit of borrowing against your 'mortgage account' is that mortgages are usually the cheapest form of borrowing. In other words, you'll pay less interest on the amount you borrow!
If on the other hand, you overpay but never make any withdrawals, you can save a significant amount of interest over the life of the loan. This is because most lenders who offer this type of loan calculate the interest you pay on a daily basis (see what to look for), therefore any overpayment comes immediately off the debt and interest payments are adjusted accordingly.