While there are many factors that influence property prices, few investors will sleep more soundly than those that buy property at a price equivalent to three times the local annual salary or less. Assuming the population is not in steep decline, as in Detroit USA for example, or that there are not thousands of empty properties on the market waiting to be sold, the knowledge that a local worker should be able to buy the property back from you without breaking a sweat financially, assures a property investor that his purchase is sound and unlikely to fall in value.

On the flip side, buying in a market where three times the local salary is unlikely to buy enough space for a garden shed, never mind a garage, might cause an investor some sleepless nights. For such a market you need not look any further than London. A quick search on Rightmove for a one-bed flat with off-street-parking anywhere with a London postcode, revealed that the median price (taking out 45% of the cheapest and 45% of the most expensive), you can now expect to pay is between £275,000 (ex-council) and £340,000 (conversion).

If the average salary for a London worker were £100,000 a year, then a purchase would make perfect sense. However, according to Payscale.com the average annual salary in London at the moment is just over £35,000.