CHOOSING an investment is not as simple as picking the top-performing fund, whose future success is not guaranteed. Before you select your portfolio, you should also consider how long you are prepared to invest.

You are taking a big risk if you cannot afford to invest in a stock market for more than five years. Bank and building society accounts often produce higher returns over shorter periods.

But there have been only one or two full five-year spells since the second world war when you would have made more money in a local bank or building society than in the British stock market.

If you can leave your investments for 10 or 15 years, you can take a bigger gamble than someone who has less time – and could reap a bigger reward. We asked the experts to recommend investments based on how long you want to tie your money up.

Up to 3 years: There will always be people who do not want to commit their cash for five years - students, for example, or those who only have emergency savings.

"Three years is too short a time for anything other than cash deposit accounts," says Ian Millward of Chase de Vere, an independent adviser. He recommends the Leeds & Holbeck cash Isa, paying 6.75% guaranteed for three years. Egg pays 6%, but is available only over the internet.

You could also consider building-society bonds, such as Abbey National's two-year bond, paying 6.85%.

Up to 5 years: if you can invest for five years, you can consider the stock market. But you should probably take a low-risk approach. Corporate bond funds are a good first step. The funds invest in bonds issued by companies to raise money for expansion. But some are riskier than others. So-called high-income funds can pay up to 8.5% a year, but they invest in bonds issued by companies that may not be financially secure. Although the yield is fixed, the value of your capital could fluctuate.

If you prefer to invest in equities, you should look at unit or investment trusts. Your money is then pooled with cash from other investors to give you a greater spread and minimise risk. A British fund is a wise choice as a core holding.

The table also shows the importance of international diversification. The ideal would be to invest in two or three funds to get as broad a spread of investments and geographical areas as possible.

Gartmore European, Fidelity International and Jupiter In-come were recommended by all the financial advisers we contacted last week.

Up to 10 years: if you have a 10-year view, you should not necessarily ignore the funds recommended for a shorter time span. However, you should be able to take a greater risk with at least some of your portfolio.

Technology funds feature heavily in this time span - SocGen's Technology fund and Framlington's Net fund are both tipped.

The funds concentrate on internet-related technology. With millions of people coming online every day and associated businesses profiting accordingly, these funds may be a good choice if you can afford to wait.

Millward says: "Look at how technological developments have accelerated during the past few years. If this pace of change continues or increases, imagine the potential rewards. Some people believe it is risky to invest in technology, but I think you are taking a greater risk if you don't."

A number of geographical regions also look promising over the next decade. However, economic evolution must also play a role if you are investing for the future. Apart from industrial or technological sectors that look promising, geographical regions incorporating several countries should also be considered.

The Far East has made a significant recovery this year and is tipped alongside Latin America. Eastern Europe is a favourite among experts who are confident that many countries in the area, including Poland, Czech Republic and Hungary, will become eligible to join the European Union within the next few years.

15 years or more: people who are confident that they can invest their money and forget about it can be more adventurous. And Japan is at the top of the high-risk list.

In 1989, Japan was worth 40% of the world's total stock market value. Today it is worth less than half that, showing how quickly an economy can turn around.

But experts are confident that, in another few years, Japan will be back to its winning ways.

Recommendations include Fidelity Japan, Martin Currie Japan and Fidelity Japanese Values. Other countries are also tipped. China, through the HSBC Hong Kong fund and Fleming Chinese Investment Trust, is thought to be particularly attractive.

Graham Bates of Bates Investment Services, an investment adviser, says: "China is potentially the largest economy in the world. There is a lot of work to do, but the signs so far are positive. The government has also accepted that it must embrace capitalism if it is to prosper."

There is no reason why you should not start off with a solid British fund, perhaps an index tracker, then gradually expand your portfolio to include Europe, America and eventually emerging markets.

However, advisers say that nobody should invest more than 5% of their portfolio in emerging economies because of the high risks. Every fund mentioned qualifies for inclusion in a tax-efficient individual savings account.

Duncan Keeler, a retired manager for British Telecom, took his first step into the stock market last year. He had previously held only BT shares through his occupational sharesave scheme. 'I just wanted to dip my toe in the water,' he says. 'I chose a low-risk portfolio, so that I could withdraw my money before too long if it didn't suit me.'

He was recommended equity funds and bond-based investments. His CGU Portfolio Bond is a mixture of a with-profits policies and a guaranteed fund. Keeler was also told to invest in two Peps last year - the first, the CGU monthly income plus, is ideal for people who want to boost their income without taking a high risk. His Invesco European Pep is slightly more adventurous, but balances out his portfolio. 'I may eventually diversify into more risky funds - my investments may have to keep me going for a long time.'

Matthew Steel, a 32-year-old IT banking consultant from Bloomsbury, central London, has a range of investments. He is planning to hold them all for at least 10 years - and most for longer.

He took out a Far Eastern fund with Jupiter some time ago and is prepared to sit it out. 'I know emerging markets are risky and I am taking a gamble of at least 15 years,' he says.

He also recently invested in a Newton Income Fund. Although it is often recommended for people who have fewer years to invest, Steel is in no hurry.

'I am planning to keep my investments for as long as possible. The longer you stay invested the more you make,' he says.

Steel is not interested in investing for the short term because of the higher risk.

'I don't see the point in cashing in after five years. If you are going to invest in the stock market, you should basically put your money in and forget all about it.'