LOYALTY may be one of the great virtues, but it certainly doesn't always get its own reward.

Not, at least, if you're a loyal customer with some of the UK's best-known High Street banks and building societies.

Despite changes in the Banking Code designed to stop savers being ripped off, a report in today's Which? magazine reveals that many banks and building societies are going all out to attract new customers with high-interest savings accounts - leaving existing savers in accounts with interest rates as low as 0.1 per cent.

Just because an account paid a good rate of interest when you opened it, the report points out, does not mean that it still does.

Unless you keep a close eye on your money, you could find the rate for your account has tumbled - and that you are getting a raw deal compared to newer customers with more recent accounts.

Among the institutions singled out in today's report are The Woolwich, whose easy-access Prime Gold account offers an interest rate of just 0.5 per cent, Abbey National, with the Instant Saver account offering 0.5 per cent for savings of less than £2,500, and Northern Rock, with its Instant Access account offering a rate as low as 0.65 per cent for savings below £500.

Other institutions offering rates lower than 1.4 per cent for savers in easy access long-term accounts which are still classed as 'live' include the Cheltenham and Gloucester (1.3 per cent with the Cheltenham Gold account) and Royal Bank of Scotland (0.95 per cent with the Gold Deposit account), the report says.

Many of the accounts identified offered high rates of interest when savers opened them. But they have fallen steadily in relation to new accounts over the last few years - without many savers realising, the report claims.

When Chris Sykes invested £12,000 with The Woolwich's Prime Gold account in 1990, he was attracted by the competitive 9.15 per cent.

He kept the account for years, rarely visiting his branch - and was shocked when a tax certificate showed that in 1999-2000 he'd earned only £47 interest, rather than the £300 he was expecting.

When he visited his branch, he was told Prime Gold was 'obsolete', and paid an interest rate of just over 0.5 per cent.

Which? editor Helen Parker today called for the Banking Code to be tightened still further so banks and building societies could not keep on getting away with keeping savers in old accounts that have effectively been superseded by newer, better accounts.

And she urged savers who found themselves stuck in poor-paying accounts to vote with their feet and switch accounts.

Liz Levitt, head of trading standards in York, said today that while most banks and building societies were improving, some were still better at informing customers of interest rate changes on accounts than others.

If savers wanted to make sure they were getting the best deal, the only way was to review their savings regularly, she said - and check with their branch what accounts were available, and what rates were being offered.

Woolwich spokeswoman Ann Pilkington stressed today that the building society fully complied with the Banking Code. Details of accounts and interest rates were advertised in the national press and posted up in branches, she said - and customers could ring up to check at any time.

The society also mailed customers with details of all the accounts and interests rates they attracted every year.

She added some customers liked to use the Prime Gold account just as somewhere to keep their money, because it was instant access with no penalty, and had a passbook.