Two NOP polls have been published within 24 hours of each other.
On Tuesday NOP for C4's 'Powerhouse' programme gave Labour 49% (down 2% on the previous week) the Conservatives 34% (up 5%) and the Lib Dems 11% (down 2%).
The fieldwork straddled 1-6 May. The second poll by NOP, for the Daily Express on Wednesday, gave Labour 51%, the Conservatives 31% and the Lib Dems 13%.
The fieldwork for the second poll overlapped the first but finished more recently (4-7 May).
The Express poll asked respondents to measure the strength, adequacy or weakness of the three main party leaders.
It found that 31% of respondents judged Mr Blair a "strong" leader and that Mr Hague came third on this measure, 13% thought him strong, compared with 17% who thought the same of Charles Kennedy.
Looking at the other side of the coin, whereas 23% thought Mr Blair a "weak" leader (and 22% thought the same of Mr Kennedy, some 44% regarded William Hague as weak.
The electorate at the start of the campaign appears to be in a grudging mood: some 54% say that Labour's record of keeping promises has been no different than the previous Conservative government, although 29% say they have been better.
Although this compares with 14% who say they have been worse. Almost half (49%) say that Labour's record in office has been "ok", compared with 22% who say it has been "good" and 28% who judge their record as "poor".