The BPIX poll for the Mail on Sunday newspaper showed Labour trailing 23 points behind the Conservatives - with support of 26 percent for Brown's party versus 49 percent for the opposition.
The poll, which surveyed 2,385 people between Wednesday and Friday last week, also found that 85 percent of voters think Brown has performed worse since taking over as prime minister from Tony Blair last June than they had expected.
Forty-four percent think he should resign now.
Brown enjoyed a brief political "honeymoon" after he took over from Blair on June 27 last year, but has been battered by economic woes, industrial strife and government blunders in recent months.
Many analysts now believe that only a dramatic upturn in the economy - unlikely in the near future - could save him at the next general election which is due by May 2010.
Finance Minister Alistair Darling admitted on Sunday that it had been a tough first year for Brown as prime minister, but insisted he would fight back.
"We have had a difficult year, whether it's the economy or other political issues," Darling told BBC television. He added: "I have always taken the view that we can turn this around".
