Credit might be getting tighter and the easy money is certainly gone from the table but, rather than calling it a day, investors have simply changed tack.

Instead of going it alone in an increasingly unpredictable market, novice investors, in particular, are opting for property surrogates.

The latest twist on the property story comes from National Irish Bank, which is offering the chance to track the growth in British house prices over the next three years (see Moneybox below).

It sounds like a good idea, especially if you're saving to get a start on the property ladder and want your money to keep pace with house prices.

But why would anybody in Ireland want to track house prices in Britain? It has different interest rates, a different currency, different demographics and more restrictive planning laws that severely limit the number of new houses that can be built.

Even though house prices in Ireland and the UK have moved roughly in the same direction . . .upwards and upwards again . . . there is no good reason to believe this relationship will continue.

That is the trouble with surrogates. They come close to doing what you want, but might not deliver exactly what you expected.

National Irish Bank is presumably tracking British prices because it was much easier to design a financial product linked to one of Europe's biggest housing markets rather than an overheated one on the periphery. It's just a pity that the target market is people who happen to live on the periphery.

Another popular proxy for direct investment in bricks and mortar is to buy shares in property companies. On paper, this also looks like a good idea.

These companies have huge portfolios, allowing you spread your investment across more properties and markets that you could ever manage under your own steam. To spread the risk even further, you can buy into a unit-linked fund that holds shares in lots of different property companies.

The beauty of this approach is that you have none of the liquidity problems encountered by people who invest directly in property, which can languish on the market for months before finding a buyer. When you are ready to cash in your investment, you simply offload the shares.

The trouble with this hybrid approach is that you can get caught in crosswinds coming from all directions. If the property market hits the buffers, the shares will take a beating. If property holds its own but the stock market gets the jitters, it's the same story.

The best substitute for owning property yourself is to invest with others through a property fund.

This gives the diversification you need without having to worry about which way the wind is blowing on the stock market.

Even so, as the closest substitute to owning property yourself, funds share many of the same pitfalls. Chief among them is the liquidity issue, and funds will only take in new money if they believe there is a property worth buying.

This is a tough task at the moment and level-headed fund managers increasingly find themselves up against cash-rich property developers, who seem to be motivated as much by ego as commercial logic.

Hibernian bit the bullet earlier this year when it forked out for part of AIB's landmark headquarters in Ballsbridge, a transaction that allowed it reopen its Irish property fund to new business. But having taken in more than 10m in four weeks, the shutters will probably be coming down again before too long.

The liquidity issue can also work against you when the time comes to cash in your investment, especially if a lot of other investors are heading for the exits at the same time.

If the fund does not hold enough cash to pay off everybody, it can lock you in for up to six months while it buys itself some time to liquidate part of its holdings.