THE first thing to note about figures released by the Halifax today claiming mortgages are at their most affordable for 14 years is that this is not the same as homes being more affordable; not in the sense that properties are any cheaper, or that incomes have increased to enable people to buy them more easily.

While some purchasers may be better off and the price of some properties has fallen, there is no doubt that the main reason mortages are easier to afford is the dramatic difference between the Bank of England's 5.25% base interest rate in 1999 and the 0.5% base rate today.

The practical effect would appear to be the same - the average home now costs 27% of its owner's income in mortgage payments. Indeed, in Scotland the figure is even lower at 19%. This is a dramatic reduction from the 2007 peak of 48%, 36% in Scotland.

According to the Halifax this is a boost for those who already have a mortgage and for first time buyers who can raise the required deposit to buy a home.

It is true that significant numbers of would-be home buyers have been shut out of the market due to the requirement for high deposits.

Maybe the apparent affordability of the market will mean some can feel more confident in taking the plunge into the housing market.

But there is more to this than meets the eye. Soaring fuel prices, food bills and the lack of any immediate prospect of pay rises for many workers mean that households today are having to tread a much more careful line.

While increased housing demand may be supporting a modest recovery, the impact of an extended period of austerity has to be taken into account. In 1999 the economic outlook was very much brighter.

In that context, affordability is a much more complex calculation for would be home-buyers than simply the amount borrowed and the proportion of income which that represents.

Following swiftly after claims by the Royal Institute of Chartered Surveyors that Scotland's housing market may be recovering, with more sales and higher final agreed prices, and with an expansion of the Chancellor's Help to Buy scheme, the latest figures may presage a surge in house prices.

High deposits help ensure that people taking on the financial burden of home ownership are those who can really afford it. The Help to Buy scheme is a deliberate market distortion to bring more people into that bracket but it could have the unwanted consequence of generating another house price bubble.

Meanwhile the danger for buyers who take advantage of today's apparently generous mortgage rates is not just that rising costs of living need to be factored in, when calculating true affordability.

When, ultimately, the economy begins to recover markedly, be it in two, five or 10 years' time, banks will undoubtedly seek to raise interest rates in line with rises imposed by the Bank of England. Unless they have allowed for that possibility, today's home-buyers may find that what appears affordable today may in the future begin to look distinctly less comfortable.