Half of Briton's 10m pensioners have been forced to cut back on their spending over the last three months according to research from the Prudential.
More than 2m have gone back to work although the Pru concedes in some cases this could be just to combat boredom, while others could need the cash it says.
The findings from the life office's quarterly Retirement Index also show that 210,000 pensioners have actually broken the law or at least considering do so in order to boost their income.
Director of marketing Roger Ramsden says: “Our research shows that the need to stay abreast of financial matters doesn't stop when you leave work. The number of pensioners who feel their low household income restricts them from leading a comfortable life in retirement has consistently risen since we started the Index last year.”