Around six million people will depend on their savings interest for a significant portion of their total income, according to Investec Private Bank.
Investec's research found more than half a million people will rely on their savings to provide them with a fifth of their total income.
A survey of retired people across Britain found more than six million rely on their savings to provide them with some of their retirement income, and are being hit hard by record low interest rates.
Those who rely most heavily on their savings will be feeling the squeeze, according to Investec, and 144,000 people take half their income from savings interest.
"Elderly savers have been among the hardest hit from the succession of cuts to the Bank of England base rate, says Linda McBain, head of banking at Investec Private Bank.
"Many of these savers have accumulated significant sums over their lifetime but are now missing out on higher rates of interest by leaving their cash in savings accounts paying derisory rates."
UK pensioners aged 65 or over hold considerable assets in cash, Investec's research suggests, with an average of £32,000, equivalent to 36% of their total assets excluding property.
McBain says low interest rates mean pensioners need to think carefully about where they put their cash to ensure they are not jeopardising their retirement income with poor savings returns.
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