The pressure on David Cameron has intensified as an opinion poll showed a slump in Tory support since Gordon Brown took over as Prime Minister.
The YouGov poll for the Daily Telegraph put Labour on 41%, up six points since May and nine points ahead of the Tories who were down six on 32%.
The Liberal Democrats were up one on 16%.
Mr Cameron's own personal rating was also down sharply with just 27% saying that they believed he was proving a good leader compared to 43% in February - a drop of 16 points.
In an almost exact reversal of the position five months ago, 44% now said they did not regard him as a good leader as against 27% in February.
Asked who would make the best Prime Minister, only 19% opted for Mr Cameron, 18 points behind Mr Brown who was the choice of 37% of voters.
Overall, 34% said they were satisfied with Mr Brown as Prime Minister compared with 27% who were dissatisfied.
