There were mixed results for long-time opinion poll leaders the Conservatives in the latest survey.
The Tories maintain a healthy 13% lead over Labour, according to the YouGov poll in The Daily Telegraph, but most voters appear unconvinced about leader David Cameron.
Nearly two-thirds, or 64%, of those questioned agreed that Mr Cameron "talks a good line but it is hard to know whether there is any substance behind the words".
A total of 55% of respondents also said it was "hard to know what the Conservative Party stands for at the moment", but this was an 8% improvement on two years ago.
In terms of voting intentions, the poll showed the Tories on 40%, Labour on 27%, and the Lib Dems trailing with 18%.
When it came to the north of England, one of the key battlegrounds at the next election, Labour was still polling better, at 35% to the Tories 33%.
In other findings, 69% of voters said the Conservatives should raise the top rate of income tax for those earning more than £150,000 to help tackle high government borrowing.
Most Tory supporters also believe that his party has not abandoned Tory principles and is now a party for those with aspirations.
YouGov polled 1,573 adults between September 4 and 6.
