This week’s consumer prices index (CPI) figures show that inflation rose to 0.5pc in March, a larger than expected rise and the fastest increase in prices since 2014.

As a result, any savings account which pays a rate of less than 0.5pc is effectively costing money to save into, as its value is being eroded.

There are over 100 savings accounts currently available that pay a rate of 0.5pc or less according to Moneyfacts, including major high street names, building societies and challenger banks.

Easy access accounts are the worst performers. Lloyd’s Easy Saver pays 0.35pc for the first 12 months, reverting to a 0.25pc Standard Saver after that. Santander’s Instant Saver goes lower still, paying a rate of just 0.1pc on balances; on a £100,000 balance, that would equate to earnings of £100, or less than zero once CPI is factored in.

There are also 38 fixed rate bonds and notice accounts that pay less than 0.5pc, and 11 variable rate Isas. Natwest’s Cash Isa for instance, pays 0.25pc on balances under £25,000.

CPI has been at record lows since last January, dropping into negative territory twice during 2015. It has been rebounding since November, crossing the 0.5pc threshold last month.

Those earning a savings rate of less than 0.5pc would have been scraping a profit for the previous 13 months, but will now effectively be losing money unless they move their savings to get a better rate.

Savings rates as a whole have been on a sharp downhill trajectory, with rate cuts significantly outpacing any rises.

Consumer price inflation is the rate at which the prices of goods and services bought by households rise and fall.

The 0.5pc figure for March was higher than the market expectation with analysts forecasting an increase from 0.3pc to 0.4pc. It is the highest level since December 2014, being driven higher by air fares, clothes prices, restaurant costs and hotels bills.

Savers with money in accounts that are being outpaced by inflation could do significantly better, even with rates at their present level.

The best one year fixed-rate bond pays 1.9pc, the top easy access account pays 1.45pc and the best variable rate Isa pays 1.65pc. There are also high interest current accounts paying up to 5pc available for those willing to meet the requirements.

Rachel Springall, finance expert at Moneyfacts, said: “Providers are constantly reducing rates, which has created a race to the bottom of the best buy tables.

“With 81 easy access accounts paying 0.5pc or less, which represent 48pc of the easy access market, the need for savers to review the interest they earn has never been so important.”