Prime Minister Theresa May and the leader of the main opposition Labour Party Jeremy Corbyn, were grilled about their policies by a television audience.
Ipsos Mori interviewed 1,046 adults aged 18 and over across Great Britain by telephone between May 30 and June 1.
Pollsters said they "introduced an adjustment to allow for respondents' over-claiming their likelihood to vote, based on evidence of validated votes from the British Election Study in previous elections".
An opinion poll published on Friday showed May's Conservatives lead the opposition Labour Party by five percentage points, down sharply from 15 a little more than two weeks ago.
It marks a significant turnaround after the Tories were 19 point ahead at the start of the campaign.
May's Conservatives had 330 seats when the snap election was called in April.
Theresa May remains voters' preferred choice for prime minister although her personal rating is down six points on 50%.
The increase in the Conservative Party's lead reported by ORB contrasted with many other recent polls which have shown its lead narrowing. The Tory lead is crumbling as Election Day is approaching, while seat projections still point to a hung parliament.