The Conservative lead over Labour has narrowed to eight points, according to a latest opinion poll.
But the survey by Populus for today's Times suggested that a majority of voters have not been won over by Labour attacks on the privileged backgrounds of Tory leader David Cameron and some of his key lieutenants.
Mr Cameron has insisted that "spiteful" class war tactics would turn voters off, after Prime Minister Gordon Brown claimed the Tories' tax plans were "dreamed up on the playing fields of Eton".
Just 34 per cent of those questioned by Populus agreed that Mr Cameron's policies were aimed at "helping rich people, rather than the whole country", against 58 per cent who disagreed.
Overall, 38 per cent said they would vote Conservative (down one point compared to a similar poll last month), 30 per cent Labour (up one point) and 20 per cent Liberal Democrat (up two points).
Economic optimism had roughly doubled from its low-point earlier this year, with 35 per cent saying they expected the economy as a whole to do well over the next 12 months, against 62 per cent who said it would continue to do badly.
And voters were split on the announcements by Mr Brown and US President Barack Obama of more troops for Afghanistan, with 44 per cent in favour and 48 per cent against it.
Some 36 per cent said troops should be withdrawn now, 31 per cent that a timetable should be set for withdrawal within about a year and 27 per cent that British troops should remain until the Taliban is defeated and the situation stable.
* Populus interviewed 1,505 adults for The Times from December 4 to 6.Reuse content