Opinions span the spectrum: some predict a period of unprecedented stability and prosperity, while others fear that there will be economic chaos. Private investors should try not to lose too much sleep over the possible personal finance implications of the UK either joining, or refusing to join, the single European currency. Even if we do elect to join, we won't be going in until at least 2002.Anyone who sticks to the rule that they are investing for the long term, and adopts a broad spread of risk, should find themselves able to make their financial plans flexible enough to cope with most eventualities. Fiona Price, senior partner at Fiona Price & Partners, a London independent financial adviser, says: "It's very difficult and possibly hazardous to make plans on the basis of one economic position. The idea is to build up a portfolio of different savings and investments that offer different advantages with regard to tax, possible economic change and alterations to your own circumstances."Those who have held well-diversified portfolios for the long term have survived the effects of major economic upheavals. Most who bought shares just before the 1987 stock market crash, for example, will not be too far short of doubling their money by now.An even more relevant example was when Britain switched from a system of fixed exchange rates to floating exchange rates in 1972. Roderic Mather, director of BWD Rensburg, stockbrokers, says: "In many ways one could argue that the move involved as much potential trauma as the idea of joining or abstaining from a single currency."It produced a fair amount of volatility in the UK stock market around the time, but the market eventually took the entire episode in its stride.

There was less in the way of global investment in those days, but portfolios diversified between different asset classes were not too badly affected."Most predictions as to how the British or continental European economies will perform following the launch of the single currency are little more than guesswork. There is much to be said for not making any asset allocation changes at this stage. You should have an annual financial review with a professional adviser so changes can be made when more information becomes available.The possible exceptions to this rule are aspects of financial planning that are highly sensitive to future interest-rate levels. This will include fixed-rate mortgages, gilts and other fixed-interest investments, and retirement annuities.The only assumption that it seems reasonable to make about the entire single currency episode is that it should result in a sustained period of lower interest rates. The consensus is that UK base rates will average around 4 per cent if we join and around 5 or 6 per cent even if we don't.Many financial planning experts are advising against taking out fixed- rate mortgages for periods of longer than three years as this could mean becoming locked into unattractively high rates.Some, however, point out that fixed rates reflect money market expectations that rates will fall, and argue that five-year deals at around 6 per cent represent good value considering they are 2.5 percentage points below many variable rates.They stress also that fixed-rate mortgages remain valuable as they allow you to plan your outgoings with certainty.Retirement planning is another area to be considered.

Lower interest rates mean lower gilt yields, leading in turn to lower annuity rates as conventional annuity providers cover their commitments primarily by investing in gilts.At first glance this sounds like bad news for those nearing retirement who have personal pension plans or who are members of a company scheme that operates on a similar "money purchase" basis. They have to use the pot of money they have built up over the years to buy an annuity - a regular income for the rest of their lives. The level of this income is determined partly by annuity rates at the time of purchase.But this is also partly influenced by the size of the pot of money available to buy the annuity. This should rise in value to offset the effects of falling annuity rates. This is because rising gilt prices, which go hand in hand with falling gilt yields, have traditionally been accompanied by rising equity prices.

Furthermore, equities have always tended to outperform gilts in the long term. Billy Burrows, managing director of William Burrows Annuities, says: "Those who have been hoping annuity rates will rise should not defer taking their pensions any longer, but at the same time people shouldn't be looking to bring forward retirement dates."Rising fund values should counteract falling annuity rates and there's no point in having to pay tax on your pension when you can leave it to roll up tax-free."It is possible, of course, that fund values and annuity rates could fall together, so there is much to be said for not having all one's eggs in the same basket. Press the on-screen help button and the phone gives the option of calling Barclays' customer helpline. The phone will also call up the bank for some transactions, such as arranging an overdraft or paying a bill, which the screenphone does not yet support electronically.Barclays is marketing the screenphone on convenience, says Gordon Rankin, managing director of personal banking. Customers will use a special handset, which Barclays plans to sell for pounds 99, to access their current account details, view a mini-statement and search for a recent transaction. If they have a Barclaycard, they can use the phone to check their account.Most of the information is displayed on a small pager-like screen built in to the telephone. This doubles as the interface for the banking service and a smart telephone directory.

The telephone itself is becoming more sophisticated and powerful, providing a base for on-line services without the complexity and expense of the net. Phones can have screens displaying text and graphics, infra-red keyboards and smart card readers, yet still cost just a few hundred pounds. This week Barclays Bank announced a new screenphone-based banking and information service. After 1 July 2002 there won't be any local money: each national version of the euro will be slightly different and will carry the international symbol on one side and a local design on the other.q Citibank and Cater Allen are planning to have bank accounts run in euros ready for 1 January 1999 Other banks are expected to follow. The rise of the internet has not stopped companies from developing phone- based services. THE HUMBLE telephone is the one piece of communications technology found in almost every household.