The disappointing poll rating comes after it emerged last week that Mr Brown had ignored Treasury warnings that his 1997 decision to scrap tax relief on share dividends could create a £75 billion pensions black hole.
Despite insisting that the move was the "right decision" for Britain at the time, the chancellor's image was also damaged after the Confederation of British Industry (CBI) dismissed his claims that the business group had lobbied him to implement the change.
In light of the debacle Mr Brown's stewardship of the economy - previously his strongest asset – has also been called into question, with fewer people now confident in his abilities as chancellor.
Just 41 per cent of respondents in the Sunday Times poll said they thought he had been a good chancellor, down from 51 per cent a month ago, while 52 per cent think that he has done a bad job.
The disappointing ratings are reflected in a second ICM survey for the News of the World, in which 57 per cent of people said they held Mr Brown responsible for Britain's current pensions shortfall, while a further 44 per cent thought that the chancellor's handling of pensions would impede his chances of winning the next election if he becomes the next Labour leader as expected.
And in a concerning result for the government ahead of next month's local, Scottish and Welsh elections, the YouGov poll of 2,218 people shows that the Conservatives have increased their lead over Labour to eight points. David Cameron's party now enjoy the support of 39 per cent of voters, compared to 31 per cent for Labour and 16 per cent for the Liberal Democrats.
Meanwhile, concern about the impact a Brown premiership could have on Labour has prompted John Reid to urge environment secretary David Miliband to challenge the chancellor for the leadership of the party once Mr Blair stands down, the Sunday Telegraph reports, citing friends of the home secretary.
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