Conservatives and Labour are neck-and-neck on 34 points in the penultimate FT/Populus poll before Thursday's election, with neither side yet breaking the election stalemate.
The poll puts David Cameron's party and Mr Miliband's Labour up one point on the 33 they scored last Friday, while the Liberal Democrats are now on 10, Ukip on 13 and others on 10.
Rick Nye, Populus managing director, said he expected any movement in the polls to take place over the next 48 hours, as voters make their final calculations on how to vote.
"If there is any hardening or softening of any party's vote share it will happen close to polling day," he said.
Conservative strategists hope that voters will make a final switch to the "security" offered by a continuation of a Tory government, similar to the trend that put John Major back into power in 1992.
Mr Nye said there could be some increase in the Lib Dem share as people consider voting tactically in individual seats. The Ukip vote is also holding up well but could yet be squeezed on polling day.
Populus will conduct more fieldwork in the next 48 hours in the hope of capturing any final movements of voters.
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