Savers were warned last week that billions of pounds are languishing in accounts that are losing value in real terms after inflation hit new highs.

Top-rate taxpayers are unable to achieve a positive real return on money in any taxable savings account, while basic-rate taxpayers are finding it increasingly difficult. Almost 35% of cash Isas – which pay interest free of tax – also fail to beat inflation.

The retail prices index (RPI) spiked to 5% in July, meaning higher-rate taxpayers need to achieve a gross return of 8.33% and basic-rate payers 6.25% just to keep pace. With the top savings rate at 7.2%, higher-rate taxpayers have no chance unless they look at Isas. “You may as well spend it all now because it will only buy less in future,” said Andy Gadd of adviser Lighthouse.

The picture is not much brighter for basic-rate payers. Just 14% of notice, nonotice, fixed rate and regular savings accounts – 278 out of the 1,980 available – have rates above 6.25% on £10,000 balances, said price-comparison site Moneyfacts. That falls to 13% when accounts with introductory bonuses are stripped out.

Household names are among the worst offenders: less than a quarter of these inflation-beating accounts come from high-street banks. Almost half (46%) are offered by building societies.

The Halifax’s best account, for example, pays 6% – a negative return of 2.33% if you are a higher-rate payer and 0.25% if you are on the basic rate. Meanwhile, HSBC’s top account open to all savers pays a paltry 2.47% if you make withdrawals, losing top-rate taxpayers 5.86% and lower-rate payers 3.78%.

This torrid time for savers comes as cash savings have soared. A record amount flowed into building society cash accounts during the first half of the year, as consumers took a “flight to safety” from volatile stock markets. Inflows totalled £6.2 billion, more than 60% up on the £3.8 billion deposited during the first half of 2007, the Building Societies Association said.

To make matters worse, many of the top savings accounts come with stringent conditions, locking people in for a fixed time or prohibiting changes to regular savings amounts. More than 80% of inflation-beating accounts for basic-rate taxpayers – 223 out of 278 – are fixed-rate products, tying savers in for six months or more. India’s ICICI Bank has the top rate at 7.2% on its Hisave bond (with a minimum deposit of £1,000), but that locks in investors for a year, as do bonds from National Counties building society and First Save, paying 7.11% and 7.1% respectively.

“As you can’t access your money without penalty, these are unpopular with most savers,” said Michelle Slade at Moneyfacts.

Some regular savings products also beat inflation for basic-rate taxpayers, but these fix or cap the amount that can be saved. Chelsea building society pays 8%, but this includes a 3% bonus in the first year, 2% in the second and 1% in the third, and savers must invest the same sum each month, up to a total £500,000.

Many of the top accounts that give savers access to their cash have rates little over 6.25%. The top account is from Heritable Bank at 6.6% – giving lower-rate taxpayers a meagre 0.35% real return. Customers must also give 60 days’ notice to withdraw their money and the rate includes an introductory bonus of 0.6% for 12 months.

Tax-free cash Isas, into which £3,600 can be stashed every tax year, offer greater hope of beating inflation – but 34.6% of these are also losing investors money. Just 153 out of 234 cash Isas – 65.4% – pay 5% or more, based on the full £3,600 investment.

The top Isa, according to comparison site Moneysupermarket, is 6.5% with Market Harborough building society, followed by 6.37% with Principality. However, both require a minimum balance of £3,600.

Inflation, as measured by the consumer prices index (CPI), the government’s preferred measure, is now at its highest level since 1992. It hit 4.4% in July, up a record 0.6%, taking financial markets by surprise; economists had forecast a rise to 4.1%. RPI – often a more realistic measure for consumers as, unlike CPI, it includes the costs of running a home, such as mortgage interest and council tax – rose to 5% from 4.6% in June.

However, there might be some respite in the offing. The Bank of England said last week that it expects CPI to spike close to 5% this year before tumbling as the effect of rising food and fuel prices wanes and the economy grinds to a standstill. That would give scope for a cut in interest rates in late 2008 or early 2009 – a move that would ease the pressure on hard-pressed homeowners.

“The slowing in growth will prompt rate cuts by early next year once the peak in inflation has passed,” said George Buckley, chief economist at Deutsche Bank.

Experts said it would be worth snapping up a fixed rate inflation-beating account now. “With swap rates falling sharply in the past two weeks, some of the highest fixed rate bonds have already been pulled, so you’ll need to be quick if you want to grab one of the top deals that remain,” said Andrew Hagger at Moneynet.co.uk.