Alliance & Leicester and HSBC have become the latest high street banks to hit savers with excessive rate cuts after announcing reductions of up to 0.5 percentage points.

Experts condemned the cuts, the biggest so far following Decembers quarter point reduction in the Bank of England base rate, as “unacceptable”.

The reductions exceed decreases of up to 0.4 points by Bradford & Bingley, Halifax and Nationwide, announced last week. Other banks to have reduced rates by more than 0.25 points include Clydesdale and Yorkshire Banks, Royal Bank of Scotland, Natwest and Sainsburys.

The recent cuts mean that the average savings pot in the UK is now effectively worthless in real terms, according to Moneyfacts.co.uk, the financial data website, as it has brought the average gross return down to 4 per cent - below the current level of RPI inflation, at 4.3 per cent.

From today, an investor with up to £10,000 in an HSBC Preferential Flexible Saver account will receive a rate of 2.91 per cent, down by 0.49 points.

A&L, which prides itself on offering customers better rates than its major high street competitors, is now paying less than 1 per cent interest on deposits in Instant Access accounts. A saver with £10,000 invested is now receiving a paltry 0.9 per cent, down from 1.40 per cent, while savers with an A&L Online Saver account will see their returns drop from 5.25 per cent to 4.75 per cent.

Lisa Taylor, of Moneyfacts.co.uk, said: “It is disappointing to see that some of the largest cuts have been made by some of the largest providers. A cut to your savings rate of more than 0.25 percentage is unacceptable. The average gross savings rate is below the current RPI figure, meaning far too many savers are investing in accounts which will see the real value of money fall over time.”

Martin Leake, manager of savings at A&L, said: “Following the base rate reduction by the Bank of England, we have reviewed our savings portfolio. Many of the changes reflect the market today and we have maintained a competitive edge on many of our products.”

Despite the cuts, Ms Taylor urged savers to stay with their current provider until after the Bank of England meets next Thursday, when some pundits expect another rate cut.

Ms Taylor said: “With another rate cut on the cards, it might be wise to stay with your existing provider for another week or so before shopping around. But once the dust has settled, don't let your bank get away with paying you a poor return or by making substantial cuts to your savings rates, vote with your feet.”